Protocols for multi-access point coordinated multi-user transmissions

ABSTRACT

Methods, systems, and devices for wireless communications are described. An access point (AP) may transmit, to a second AP and during a first portion of a transmission opportunity (TxOP), a request to participate in a multi-user (MU) transmission. The AP may receive, from the second AP and during the first portion of the TxOP, an indication of intent to participate in the MU transmission during the second portion of the TxOP, the indication of intent including a resource request of the second AP for participation in the MU transmission. The AP may transmit, during an initial period of the second portion of the TxOP, a trigger signal to the second AP indicating a set of one or more resources for the second AP during the MU transmission. The AP may participate, in conjunction with the second AP and during the second portion of the TxOP, in the MU transmission.

CROSS REFERENCE

The present Application for Patent claims the benefit of U.S.Provisional Patent Application No. 62/749,041 by Vermani, et al.,entitled “PROTOCOLS FOR MULTI-ACCESS POINT COORDINATED MULTI-USERTRANSMISSIONS” filed Oct. 22, 2018, and to U.S. Provisional PatentApplication No. 62/726,968 by Cherian, et al., entitled “MULTI-ACCESSPOINT SCHEDULING IN WIRELESS LOCAL AREA NETWORKS,” filed Sep. 4, 2018,and to U.S. Provisional Patent Application No. 62/744,626 by Cherian, etal., entitled “MULTI-ACCESS POINT SCHEDULING IN WIRELESS LOCAL AREANETWORKS” filed Oct. 11, 2018, and to and assigned to the assigneehereof, and expressly incorporated herein.

BACKGROUND

The following relates generally to wireless communications, and morespecifically to multi-access point scheduling in wireless local areanetworks and to protocols for multi-access point (AP) coordinatedmulti-user (MU) transmissions.

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). A wireless network, for example a WLAN, such as a Wi-Fi (i.e.,Institute of Electrical and Electronics Engineers (IEEE) 802.11) networkmay include AP that may communicate with one or more stations (STAs) ormobile devices. The AP may be coupled to a network, such as theInternet, and may enable a mobile device to communicate via the network(or communicate with other devices coupled to the access point). Awireless device may communicate with a network device bi-directionally.For example, in a WLAN, a STA may communicate with an associated AP viaDL and UL. The DL (or forward link) may refer to the communication linkfrom the AP to the station, and the UL (or reverse link) may refer tothe communication link from the station to the AP.

SUMMARY

The described techniques relate to improved methods, systems, devices,or apparatuses that support multi-access point scheduling in wirelesslocal area networks (WLANs). Techniques described herein provide forcoordination between multiple access points (APs), which may reduce anamount of interference between APs and provide for concurrentcommunications between multiple APs and associated stations (STAs).According to various aspects of the disclosure, a first AP may gainchannel access for a transmission opportunity (TxOP), and may coordinatewith at least a second AP to allow both the first AP and the second APto transmit and receive wireless communications during the TxOP. In somecases, the first AP, upon gaining channel access (e.g., following asuccessful contention-based channel access procedure), may initiate ascheduling phase with the second AP to schedule of resources within theTxOP for the first and second AP. The first AP may initiate a multi-APcoordinated transmission phase following the scheduling phase, duringwhich both the first AP and second AP may communicate with one or moreassociated STAs.

A method of wireless communication at a first AP is described. Themethod may include winning a contention-based procedure for atransmission opportunity of a wireless channel, transmitting to at leasta second AP, during a first portion of the transmission opportunity, afirst resource assignment for coordinated communications between thesecond AP and at least a first station during a second portion of thetransmission opportunity, transmitting to at least the second AP anindication of a start of the second portion of the transmissionopportunity, and initiating, based on the indication, coordinatedcommunications between the first AP and at least a second stationassociated with the first AP during the second portion of thetransmission opportunity.

An apparatus for wireless communication at a first AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to sense awireless channel via the first interface to win a contention-basedprocedure for a transmission opportunity of a wireless channel, output,via the second interface, for transmission to at least a second AP,during a first portion of the transmission opportunity, a first resourceassignment for coordinated communications between the second AP and atleast a first station during a second portion of the transmissionopportunity, output, via the second interface, for transmission to atleast the second AP, an indication of a start of the second portion ofthe transmission opportunity, and initiate, based on the indication,coordinated communications between the first AP and at least a secondstation associated with the first AP during the second portion of thetransmission opportunity.

Another apparatus for wireless communication at a first AP is described.The apparatus may include means for winning a contention-based procedurefor a transmission opportunity of a wireless channel, transmitting to atleast a second AP, during a first portion of the transmissionopportunity, a first resource assignment for coordinated communicationsbetween the second AP and at least a first station during a secondportion of the transmission opportunity, transmitting to at least thesecond AP an indication of a start of the second portion of thetransmission opportunity, and initiating, based on the indication,coordinated communications between the first AP and at least a secondstation associated with the first AP during the second portion of thetransmission opportunity.

A non-transitory computer-readable medium storing code for wirelesscommunication at a first AP is described. The code may includeinstructions executable by a processor to win a contention-basedprocedure for a transmission opportunity of a wireless channel, transmitto at least a second AP, during a first portion of the transmissionopportunity, a first resource assignment for coordinated communicationsbetween the second AP and at least a first station during a secondportion of the transmission opportunity, transmit to at least the secondAP an indication of a start of the second portion of the transmissionopportunity, and initiate, based on the indication, coordinatedcommunications between the first AP and at least a second stationassociated with the first AP during the second portion of thetransmission opportunity.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving a firstscheduling indicator from the second AP based on the first resourceassignment and transmitting to a third AP and based on the firstscheduling indicator, a second resource assignment for coordinatedcommunications between the third AP and at least a third station duringthe second portion of the transmission opportunity.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving a secondscheduling indicator from the third AP based on the second resourceassignment. Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring theresource assignment in a single user (SU) physical protocol data unit(PPDU) format. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for transmittingthe resource assignment allocating resources for coordinatedcommunications between the second AP at least a first station, andbetween a third AP and at least a third station.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring theresource assignment to include an AP identifier and correspondingresources of the second portion of the transmission opportunity for atleast the second AP. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for configuring thecoordinated communications with at least the second station in amulti-AP PPDU (MAP PPDU) format or in a high efficiency trigger-basedPPDU (HE TB PPDU) format.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thecoordinated communications with at least the second station to includean AP identifier for the second AP in a station identifier (STAID)field.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thecoordinated communications with at least the second station to include amapping of an AP identifier for the second AP to corresponding resourcesof the second portion of the transmission opportunity for at least thesecond AP, where the mapping may be configured to be located in a newfield of a HE TB PPDU. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for configuring thecoordinated communications with at least the second station to include amapping of an AP identifier for the first AP to corresponding resourcesof the second portion of the transmission opportunity for the at leastthe first AP, where the mapping may be located in a reserved field of aHE TB PPDU. Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thecoordinated communications with at least the second station in a MAPPPDU format or in a HE TB PPDU format.

A method of wireless communication at a second AP is described. Themethod may include receiving, during a first portion of a transmissionopportunity reserved for communications by a first AP, a resourceassignment from the first AP to schedule coordinated communications overa second portion of the transmission opportunity, transmitting ascheduling indicator to at least one station associated with the secondaccess point scheduling a subset of resources of the second portion ofthe transmission opportunity for the coordinated communicationsindicated in the resource assignment, receiving an indication of a startof the second portion of the transmission opportunity, and initiating,based on the indication, coordinated communications between the secondAP and the at least one station during the second portion of thetransmission opportunity.

An apparatus for wireless communication at a second AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to obtain, viathe first interface, during a first portion of a transmissionopportunity reserved for communications by a first AP, a resourceassignment from the first AP to schedule coordinated communications overa second portion of the transmission opportunity, output, via the secondinterface, a scheduling indicator to at least one station associatedwith the second access point scheduling a subset of resources of thesecond portion of the transmission opportunity for the coordinatedcommunications indicated in the resource assignment, obtain, via thefirst interface, an indication of a start of the second portion of thetransmission opportunity, and initiate, based on the indication,coordinated communications between the second AP and the at least onestation during the second portion of the transmission opportunity.

Another apparatus for wireless communication at a second AP isdescribed. The apparatus may include means for receiving, during a firstportion of a transmission opportunity reserved for communications by afirst AP, a resource assignment from the first AP to schedulecoordinated communications over a second portion of the transmissionopportunity, transmitting a scheduling indicator to at least one stationassociated with the second access point scheduling a subset of resourcesof the second portion of the transmission opportunity for thecoordinated communications indicated in the resource assignment,receiving an indication of a start of the second portion of thetransmission opportunity, and initiating, based on the indication,coordinated communications between the second AP and the at least onestation during the second portion of the transmission opportunity.

A non-transitory computer-readable medium storing code for wirelesscommunication at a second AP is described. The code may includeinstructions executable by a processor to receive, during a firstportion of a transmission opportunity reserved for communications by afirst AP, a resource assignment from the first AP to schedulecoordinated communications over a second portion of the transmissionopportunity, transmit a scheduling indicator to at least one stationassociated with the second access point scheduling a subset of resourcesof the second portion of the transmission opportunity for thecoordinated communications indicated in the resource assignment, receivean indication of a start of the second portion of the transmissionopportunity, and initiate, based on the indication, coordinatedcommunications between the second AP and the at least one station duringthe second portion of the transmission opportunity.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thescheduling indicator in a SU PPDU format. Some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein may further include operations, features, means, or instructionsfor configuring the scheduling indicator in a MAP PPDU format. Someexamples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thescheduling indicator to include, in a scheduling indicator preamble, anAP identifier for the second AP and a corresponding subchannelindication for the at least one station to monitor for a schedulingindicator payload.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving, in theresource assignment, information indicative of the correspondingsubchannel for the second AP and transmitting the scheduling indicatorpayload over the corresponding subchannel based on the resourceassignment.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for transmitting thescheduling indicator preamble over a channel simultaneously with atleast a third AP, where the scheduling indicator further includes an APidentifier for the third AP and a corresponding subchannel indicationfor the at least a second station associated with the third AP tomonitor for a scheduling indicator payload. In some examples of themethod, apparatuses, and non-transitory computer-readable mediumdescribed herein, the channel includes a primary channel for the firstAP. Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thescheduling indicator to include an AP identifier for the second AP in aSTAID field.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for configuring thecoordinated communications with the at least one station to include amapping of an AP identifier for the second AP to corresponding resourcesof the second portion of the transmission opportunity for at least thesecond AP where the mapping may be configured to be located in a newfield of a HE TB PPDU. Some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for configuring thescheduling indicator to include a mapping of an AP identifier for thesecond AP to corresponding resources of the second portion of thetransmission opportunity for at least the second AP, where the mappingmay be configured to be located in a reserved field of a HE TB PPDU.

A method of wireless communication at a station is described. The methodmay include receiving, during a first portion of a transmissionopportunity and from an AP, a scheduling indicator configured toschedule a set of resources of a transmission opportunity forcoordinated communications, the transmission opportunity reserved forcommunications by a first AP and initiating coordinated communicationswith the second AP and over the subset of resources of the transmissionopportunity based on the scheduling indicator.

An apparatus for wireless communication at a station is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to obtain, viathe first interface, during a first portion of a transmissionopportunity and from an AP, a scheduling indicator configured toschedule a set of resources of a transmission opportunity forcoordinated communications, the transmission opportunity reserved forcommunications by a first AP and initiate coordinated communicationswith the second AP and over the subset of resources of the transmissionopportunity based on the scheduling indicator.

Another apparatus for wireless communication at a station is described.The apparatus may include means for receiving, during a first portion ofa transmission opportunity and from an AP, a scheduling indicatorconfigured to schedule a set of resources of a transmission opportunityfor coordinated communications, the transmission opportunity reservedfor communications by a first AP and initiating coordinatedcommunications with the second AP and over the subset of resources ofthe transmission opportunity based on the scheduling indicator.

A non-transitory computer-readable medium storing code for wirelesscommunication at a station is described. The code may includeinstructions executable by a processor to receive, during a firstportion of a transmission opportunity and from an AP, a schedulingindicator configured to schedule a set of resources of a transmissionopportunity for coordinated communications, the transmission opportunityreserved for communications by a first AP and initiate coordinatedcommunications with the second AP and over the subset of resources ofthe transmission opportunity based on the scheduling indicator.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving thescheduling indicator in a SU PPDU format.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving thescheduling indicator in a MAP PPDU format. Some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein may further include operations, features, means, or instructionsfor receiving, in a scheduling indicator preamble, an AP identifier forthe second AP and a corresponding subchannel indication and monitoringthe corresponding subchannel for a scheduling indicator payload based onthe scheduling indicator preamble. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, the scheduling indicator further includes an AP identifier forthe third AP and a corresponding subchannel indication for the at leasta second station associated with the third AP to monitor for ascheduling indicator payload. In some examples of the method,apparatuses, and non-transitory computer-readable medium describedherein, the channel includes a primary channel for the first AP.

Some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein may further includeoperations, features, means, or instructions for receiving thecoordinated communications with the second AP in a MAP PPDU format or ina HE TB PPDU format. In some examples of the method, apparatuses, andnon-transitory computer-readable medium described herein, the schedulingindicator includes an AP identifier for the second AP in a STAID field.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the coordinatedcommunications with the second AP includes a mapping of an AP identifierfor the second AP to corresponding resources of the second portion ofthe transmission opportunity for at least the second AP, where themapping may be configured to be located in a new field of a HE TB PPDU.In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the scheduling indicatorincludes a mapping of an AP identifier for the second AP tocorresponding resources of the second portion of the transmissionopportunity for at least the second AP, where the mapping may beconfigured to be located in a reserved field of a HE TB PPDU.

A method of wireless communication at an AP is described. The method mayinclude configuring a MAP PPDU transmission to schedule coordinatedcommunications with at least one station, transmitting the MAP PPDUtransmission upon reception of an indication of a start of a secondportion of a transmission opportunity, and communicating with thestation based on the MAP PPDU transmission.

An apparatus for wireless communication at an AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to configure aMAP PPDU transmission to schedule coordinated communications with atleast one station, output, via the second interface, the MAP PPDUtransmission upon reception of an indication of a start of a secondportion of a transmission opportunity, and communicate with the stationbased on the MAP PPDU transmission.

Another apparatus for wireless communication at an AP is described. Theapparatus may include means for configuring a MAP PPDU transmission toschedule coordinated communications with at least one station,transmitting the MAP PPDU transmission upon reception of an indicationof a start of a second portion of a transmission opportunity, andcommunicating with the station based on the MAP PPDU transmission.

A non-transitory computer-readable medium storing code for wirelesscommunication at an AP is described. The code may include instructionsexecutable by a processor to configure a MAP PPDU transmission toschedule coordinated communications with at least one station, transmitthe MAP PPDU transmission upon reception of an indication of a start ofa second portion of a transmission opportunity, and communicate with thestation based on the MAP PPDU transmission.

A method of wireless communication at a wireless station is described.The method may include receiving a MAP PPDU transmission to schedulecoordinated communications with a AP and communicating with the AP basedon the MAP PPDU transmission.

An apparatus for wireless communication at a wireless station isdescribed. The apparatus may include a first interface, a secondinterface, and a wireless modem, where the wireless modem is configuredto obtain, via the first interface, a MAP PPDU transmission to schedulecoordinated communications with a AP and communicate with the AP basedon the MAP PPDU transmission.

Another apparatus for wireless communication at a wireless station isdescribed. The apparatus may include means for receiving a multi-APphysical protocol data unit (MAP PPDU) transmission to schedulecoordinated communications with a AP and communicating with the AP basedon the MAP PPDU transmission.

A non-transitory computer-readable medium storing code for wirelesscommunication at a wireless station is described. The code may includeinstructions executable by a processor to receive a MAP PPDUtransmission to schedule coordinated communications with a AP andcommunicate with the AP based on the MAP PPDU transmission.

A method of wireless communication at a first AP is described. Themethod may include transmitting to at least a second AP an indication ofa start of a second portion of a transmission opportunity reserved forcommunications by the first AP and initiating, based on the indication,coordinated communications between the first AP and at least one stationassociated with the first AP during the second portion of thetransmission opportunity.

An apparatus for wireless communication at a first AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to output, viathe second interface, for transmission to at least a second AP, anindication of a start of a second portion of a transmission opportunityreserved for communications by the first AP and initiate, based on theindication, coordinated communications between the first AP and at leastone station associated with the first AP during the second portion ofthe transmission opportunity.

Another apparatus for wireless communication at a first AP is described.The apparatus may include means for transmitting to at least a second APan indication of a start of a second portion of a transmissionopportunity reserved for communications by the first AP and initiating,based on the indication, coordinated communications between the first APand at least one station associated with the first AP during the secondportion of the transmission opportunity.

A non-transitory computer-readable medium storing code for wirelesscommunication at a first AP is described. The code may includeinstructions executable by a processor to transmit to at least a secondAP an indication of a start of a second portion of a transmissionopportunity reserved for communications by the first AP and initiate,based on the indication, coordinated communications between the first APand at least one station associated with the first AP during the secondportion of the transmission opportunity.

A method of wireless communication at a second AP is described. Themethod may include receiving an indication of a start of a secondportion of a transmission opportunity reserved for communications by afirst AP and initiating, based on the indication, coordinatedcommunications between the second AP and at least one station during thesecond portion of the transmission opportunity.

An apparatus for wireless communication at a second AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to obtain, viathe second interface, an indication of a start of a second portion of atransmission opportunity reserved for communications by a first AP andinitiate, based on the indication, coordinated communications betweenthe second AP and at least one station during the second portion of thetransmission opportunity.

Another apparatus for wireless communication at a second AP isdescribed. The apparatus may include means for receiving an indicationof a start of a second portion of a transmission opportunity reservedfor communications by a first AP and initiating, based on theindication, coordinated communications between the second AP and atleast one station during the second portion of the transmissionopportunity.

A non-transitory computer-readable medium storing code for wirelesscommunication at a second AP is described. The code may includeinstructions executable by a processor to receive an indication of astart of a second portion of a transmission opportunity reserved forcommunications by a first AP and initiate, based on the indication,coordinated communications between the second AP and at least onestation during the second portion of the transmission opportunity.

In addition, the described techniques may relate to improved methods,systems, devices, or apparatuses that support protocols for multi-APcoordinated MU transmissions. The described techniques may provide amulti-phase/stage approach that supports a coordinated multi-user (MU)transmission. Broadly, aspects of the described techniques provide amechanism for a master access point (AP) to dynamically allocate anappropriate amount of resources to slave AP(s) participating in a MUtransmission. Broadly, the described techniques for a coordinated a MUtransmission may generally be divided into a resource offer and requestphase and a triggered transmission phase, with each phase having its ownset of stages.

For example, in stage 1 of the resource offer and request phase themaster AP may obtain access to a channel during a transmissionopportunity (TxOP) that includes more resources that are needed by themaster AP. Accordingly, the master AP may transmit or otherwise providean indication of a request to participate (or invitation to participate)in a coordinated a MU transmission to one or more slave AP(s) (which mayalso be considered neighboring AP(s) from the perspective of themaster's AP).

In stage 2 of the resource offer and request phase, the slave AP(s) thatreceive the request to participate and have data to communicate duringthe TxOP may respond by transmitting or otherwise providing anindication of an intent to participate in the MU transmission to themaster AP. In some aspects, the indication of intent to participateindication may also carry or convey an indication of a resource requestfor the corresponding slave AP.

In stage 3 of the triggered transmission phase, the master AP maytransmit or otherwise provide an indication of the trigger signal toslave AP(s) that confirms the slave AP(s) participating in the MUtransmission and carries or otherwise conveys an indication of a requestfor resources for the slave AP(s) to use during the MU transmission. Anoptional stage 3a of the triggered transmission phase may also beincluded where channel sounding (e.g., power measurements) may beperformed between AP(s), between AP(s) and their associated wirelessstations, and/or between wireless stations.

In stage 4 of the triggered transmission phase, the coordinated a MUtransmission may be performed between the AP(s) and their associatedwireless stations. The MU transmission may be uplink and/or downlinktransmissions.

A method of wireless communication at a first AP is described. Themethod may include transmitting, to a second AP and during a firstportion of a TxOP, a request to participate in a MU transmission duringa second portion of the TxOP, receiving, from the second AP and duringthe first portion of the TxOP, an indication of intent to participate inthe MU transmission during the second portion of the TxOP, theindication of intent including a resource request of the second AP forparticipation in the MU transmission, transmitting, during an initialperiod of the second portion of the TxOP, a trigger signal to the secondAP indicating a set of one or more resources for the second AP duringthe MU transmission, and participating, in conjunction with the secondAP and during the second portion of the TxOP, in the MU transmission.

An apparatus for wireless communication at a first AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to output via thesecond interface for transmission to a second AP and during a firstportion of a TxOP, a request to participate in a MU transmission duringa second portion of the TxOP, obtain, via the first interface, from thesecond AP and during the first portion of the TxOP, an indication ofintent to participate in the MU transmission during the second portionof the TxOP, the indication of intent including a resource request ofthe second AP for participation in the MU transmission, output, via thesecond interface for transmission during an initial period of the secondportion of the TxOP, a trigger signal to the second AP indicating a setof one or more resources for the second AP during the MU transmission,and participate, in conjunction with the second AP and during the secondportion of the TxOP, in the MU transmission.

Another apparatus for wireless communication at a first AP is described.The apparatus may include means for transmitting, to a second AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP, receiving, from thesecond AP and during the first portion of the TxOP, an indication ofintent to participate in the MU transmission during the second portionof the TxOP, the indication of intent including a resource request ofthe second AP for participation in the MU transmission, transmitting,during an initial period of the second portion of the TxOP, a triggersignal to the second AP indicating a set of one or more resources forthe second AP during the MU transmission, and participating, inconjunction with the second AP and during the second portion of theTxOP, in the MU transmission.

A non-transitory computer-readable medium storing code for wirelesscommunication at a first AP is described. The code may includeinstructions executable by a processor to transmit, to a second AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP, receive, from thesecond AP and during the first portion of the TxOP, an indication ofintent to participate in the MU transmission during the second portionof the TxOP, the indication of intent including a resource request ofthe second AP for participation in the MU transmission, transmit, duringan initial period of the second portion of the TxOP, a trigger signal tothe second AP indicating a set of one or more resources for the secondAP during the MU transmission, and participate, in conjunction with thesecond AP and during the second portion of the TxOP, in the MUtransmission.

Some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for configuring thetrigger signal to indicate that channel sounding may be to be performedbetween transmission of the trigger signal and a beginning of the MUtransmission, and performing a channel sounding procedure between thefirst AP and one or more stations associated with the first AP duringthe channel sounding.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, participatingin the MU transmission may include operations, features, means, orinstructions for transmitting a control channel assignment message toeach of one or more stations associated with the first AP that may beassociated with the MU transmission that assigns a control channel foreach station to use to determine a resource allocation for the MUtransmission, and transmitting, in the assigned control channel andbefore a data transmission during the MU transmission, the resourceallocation for each station to use for the MU transmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the controlchannel assignment message may be transmitted in a different physicallayer protocol data unit than the data transmission of the MUtransmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the controlchannel assignment message may be transmitted in a preamble of a secondtrigger signal before the multi-user transmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the controlchannel assignment message may be transmitted in a preamble of the datatransmission.

Some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for obtainingaccess to the channel of the shared radio frequency spectrum band forthe TxOP.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a duration ofthe TxOP, an available bandwidth for the MU transmission, an availablespatial dimension for the MU transmissions, a configuration for thesecond AP to transmit the indication of intent, a scheduling for thesecond AP to transmit the indication of intent, a transmission directionfor the MU transmission, an allowable interference level for the firstAP, an identifier of the second AP, an identifier for a group of APsparticipating in the MU transmission, a transmit power of the first AP,or a combination thereof.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a simultaneoustransmission, a scheduled transmission, or a polled transmission fromthe second AP and one or more additional APs participating in the MUtransmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the indicationof intent further indicates a channel power measurement request for oneor more stations to measure a channel power using the trigger signal.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a guardinterval duration for the MU transmission, a preamble configuration forthe MU transmission, a transmission direction for the MU transmission,an allowable interference level for the first AP, an indication of achannel sounding stage between the trigger signal and a beginning of theMU transmission, or a combination thereof.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a timeresource, a frequency resource, a spatial dimension resource, anorthogonal resource, or a combination thereof.

A method of wireless communication at a second AP is described. Themethod may include receiving, from a first AP and during a first portionof a TxOP, a request to participate in a MU transmission during a secondportion of the TxOP, transmitting, to the first AP and during the firstportion of the TxOP, an indication of intent to participate in the MUtransmission during the second portion of the TxOP, the indication ofintent including a resource request of the second AP for participationin the MU transmission, receiving, during an initial period of thesecond portion of the TxOP, a trigger signal from the first APindicating a set of one or more resources for the second AP during theMU transmission, and participating, in conjunction with the first AP andduring the second portion of the TxOP, in the MU transmission.

An apparatus for wireless communication at a second AP is described. Theapparatus may include a first interface, a second interface, and awireless modem, where the wireless modem is configured to output via thesecond interface for transmission to a first AP and during a firstportion of a TxOP, a request to participate in a MU transmission duringa second portion of the TxOP, output, via the second interface fortransmission to the first AP and during the first portion of the TxOP,an indication of intent to participate in the MU transmission during thesecond portion of the TxOP, the indication of intent including aresource request of the second AP for participation in the MUtransmission, obtain, via the first interface, during an initial periodof the second portion of the TxOP, a trigger signal from the first APindicating a set of one or more resources for the second AP during theMU transmission, and participate, in conjunction with the first AP andduring the second portion of the TxOP, in the MU transmission.

Another apparatus for wireless communication at a second AP isdescribed. The apparatus may include means for receiving, from a firstAP and during a first portion of a TxOP, a request to participate in aMU transmission during a second portion of the TxOP, transmitting, tothe first AP and during the first portion of the TxOP, an indication ofintent to participate in the MU transmission during the second portionof the TxOP, the indication of intent including a resource request ofthe second AP for participation in the MU transmission, receiving,during an initial period of the second portion of the TxOP, a triggersignal from the first AP indicating a set of one or more resources forthe second AP during the MU transmission, and participating, inconjunction with the first AP and during the second portion of the TxOP,in the MU transmission.

A non-transitory computer-readable medium storing code for wirelesscommunication at a second AP is described. The code may includeinstructions executable by a processor to receive, from a first AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP, transmit, to the firstAP and during the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission, receive, during aninitial period of the second portion of the TxOP, a trigger signal fromthe first AP indicating a set of one or more resources for the second APduring the MU transmission, and participate, in conjunction with thefirst AP and during the second portion of the TxOP, in the MUtransmission.

Some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for transmitting,in a single protocol data unit, the indication of intent to participateto the first AP and each of one or more stations associated with thesecond AP that may be participating in the MU transmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the singleprotocol data unit indicates an identifier for each of the one or morestations.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the singleprotocol data unit indicates a channel power measurement request for oneor more stations to measure a channel power using the trigger signal.

Some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for transmitting,in a first protocol data unit, the indication of intent to participateto the first AP, and transmitting, in a second protocol data unit, theindication of intent to participate to each of one or more stationsassociated with the second AP that may be participating in the MUtransmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the secondprotocol data unit indicates an identifier for each of the one or morestations.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the secondprotocol data unit indicates a channel power measurement request for oneor more stations to measure a channel power using the trigger signal.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the controlchannel assignment message may be transmitted in a preamble of a secondtrigger signal before the multi-user transmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the controlchannel assignment message may be transmitted in a preamble of the datatransmission.

Some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein may furtherinclude operations, features, means, or instructions for decoding thetrigger signal to determine that channel sounding may be to be performedbetween reception of the trigger signal and a beginning of the MUtransmission, and performing a channel sounding procedure between thesecond AP and one or more stations associated with the second AP duringthe channel sounding.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, participatingin the MU transmission may include operations, features, means, orinstructions for transmitting a control channel assignment message toeach of one or more stations associated with the second AP that may beassociated with the MU transmission that assigns a control channel foreach station to use to determine a resource allocation for the MUtransmission, and transmitting, in the assigned control channel andbefore a data transmission during the MU transmission, the resourceallocation for each station to use for the MU transmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the controlchannel assignment message may be transmitted in a different physicallayer protocol data unit than the data transmission of the MUtransmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a duration ofthe TxOP, an available bandwidth for the MU transmission, an availablespatial dimension for the MU transmissions, a configuration for thesecond AP to transmit the indication of intent, a scheduling for thesecond AP to transmit the indication of intent, a transmission directionfor the MU transmission, an allowable interference level for the firstAP, an identifier of the second AP, an identifier for a group of APsparticipating in the MU transmission, a transmit power of the first AP,or a combination thereof.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a simultaneoustransmission, a scheduled transmission, or a polled transmission fromthe second AP and one or more additional APs participating in the MUtransmission.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, the indicationof intent further indicates a station channel power measurement requestfor one or more stations to measure a channel receive power using thetrigger signal.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a guardinterval duration for the MU transmission, a preamble configuration forthe MU transmission, a transmission direction for the MU transmission,an allowable interference level for the first AP, an indication of achannel sounding stage between the trigger signal and a beginning of theMU transmission, or a combination thereof.

In some examples of the method, apparatuses, wireless device, andnon-transitory computer-readable medium described herein, a timeresource, a frequency resource, a spatial dimension resource, anorthogonal resource, or a combination thereof.

A method of wireless communications at a wireless station is described.The method may include receiving, from an AP, a control channelassignment message that assigns a control channel for the wirelessstation to use to determine a resource allocation for a MU transmissionduring a TxOP, receiving, in the assigned control channel and before adata transmission of the MU transmission, a resource allocation for thewireless station to use for the MU transmission, and participating,using the resource allocation, in the MU transmission with the AP.

An apparatus for wireless communications at a wireless station isdescribed. The apparatus may include a first interface, a secondinterface, and a wireless modem, where the wireless modem is configuredto obtain, via the first interface, from an AP, a control channelassignment message that assigns a control channel for the wirelessstation to use to determine a resource allocation for a MU transmissionduring a TxOP, obtain, via the first interface, in the assigned controlchannel and before a data transmission of the MU transmission, aresource allocation for the wireless station to use for the MUtransmission, and participate, using the resource allocation, in the MUtransmission with the AP.

Another apparatus for wireless communications at a wireless station isdescribed. The apparatus may include means for receiving, from an AP, acontrol channel assignment message that assigns a control channel forthe wireless station to use to determine a resource allocation for a MUtransmission during a TxOP, receiving, in the assigned control channeland before a data transmission of the MU transmission, a resourceallocation for the wireless station to use for the MU transmission, andparticipating, using the resource allocation, in the MU transmissionwith the AP.

A non-transitory computer-readable medium storing code for wirelesscommunications at a wireless station is described. The code may includeinstructions executable by a processor to receive, from an AP, a controlchannel assignment message that assigns a control channel for thewireless station to use to determine a resource allocation for a MUtransmission during a TxOP, receive, in the assigned control channel andbefore a data transmission of the MU transmission, a resource allocationfor the wireless station to use for the MU transmission, andparticipate, using the resource allocation, in the MU transmission withthe AP.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the control channelassignment message may be received in a different physical layerprotocol data unit than the data transmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the control channelassignment message may be received in a preamble of a per-AP triggersignal before the data transmission.

In some examples of the method, apparatuses, and non-transitorycomputer-readable medium described herein, the control channelassignment message may be received in a preamble of the datatransmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communicationsthat supports multi-access point scheduling in wireless local areanetworks in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a portion of a WLAN that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIG. 3 illustrates an example of a multi-AP coordination technique thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a multi-AP coordination technique thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of concurrent scheduling for multiple APsthat supports multi-access point scheduling in wireless local areanetworks in accordance with aspects of the present disclosure.

FIGS. 6A-6G illustrate examples of various multi-AP physical protocoldata units that support multi-access point scheduling in wireless localarea networks in accordance with aspects of the present disclosure.

FIG. 7A illustrates an example of a protocol sequence for downlinkorthogonal frequency division multiple access (OFDMA) that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIG. 7B illustrates another example of a protocol sequence for downlinkOFDMA that supports multi-access point scheduling in wireless local areanetworks in accordance with aspects of the present disclosure.

FIG. 7C illustrates an example of a multi-AP PPDU configuration thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure.

FIG. 8 illustrates an example of a protocol sequence for uplink OFDMAthat supports multi-access point scheduling in wireless local areanetworks in accordance with aspects of the present disclosure.

FIGS. 9 and 10 show block diagrams of devices that support multi-accesspoint scheduling in wireless local area networks in accordance withaspects of the present disclosure.

FIG. 11 shows a block diagram of a communications manager that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIG. 12 shows a diagram of a system including a device that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIGS. 13 and 14 show block diagrams of devices that support multi-accesspoint scheduling in wireless local area networks in accordance withaspects of the present disclosure.

FIG. 15 shows a block diagram of a communications manager that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIG. 16 shows a diagram of a system including a device that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIGS. 17 through 26 show flowcharts illustrating methods that supportmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure.

FIG. 27 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 28 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 29 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 30 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIGS. 31A-31C illustrate examples of a MU transmission scheme thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure.

FIG. 32 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 33 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 34 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 35 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 36 illustrates an example of a MU transmission scheme that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIGS. 37 and 38 show block diagrams of devices that support protocolsfor multi-AP coordinated MU transmissions in accordance with aspects ofthe present disclosure.

FIG. 39 shows a block diagram of a communications manager that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIG. 40 shows a diagram of a system including a device that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

FIGS. 41 through 43 show flowcharts illustrating methods that supportprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects of the present disclosure provide techniques formulti-access point (AP) scheduling and coordination in wireless localarea networks (WLANs). In some aspects of the disclosure, a scheme formulti-AP scheduling is provided, in which a first AP may gain channelaccess for a transmission opportunity (TxOP), and may coordinate with atleast a second AP to allow both the first AP and the second AP totransmit and receive wireless communications during the TxOP. In furtheraspects of the disclosure, a physical protocol data unit (PPDU) formulti-AP coordination is provided, which may carry information relatedto scheduling and transmission resources for coordination of concurrenttransmissions by multiple APs. In still further aspects of thedisclosure, techniques for orthogonal frequency division multiple access(OFDMA) are provided in which multiple APs may concurrently communicatewith one or more associated STAs using one or more wireless channels.

In some cases, a first AP may gain channel access for a transmissionopportunity (TxOP), and may coordinate with at least a second AP toallow both the first AP and the second AP to transmit and receivewireless communications during the TxOP. The first AP may be referred toas a TxOP owner, or leader AP, in accordance with various aspects of thedisclosure. In some cases, the first AP, upon gaining channel access(e.g., following a successful contention-based channel accessprocedure), may initiate a scheduling phase with the second AP toschedule of resources within the TxOP for the first and second AP. Thefirst AP may initiate a multi-AP coordinated transmission phasefollowing the scheduling phase, during which both the first AP andsecond AP may communicate with one or more associated STAs.

The scheduling phase may be initiated by the first AP transmitting,during a first portion of the TxOP, a first resource assignment (e.g.,using a multi-AP physical protocol data unit (MAP PPDU) or a highefficiency trigger-based physical protocol data unit (HE TB PPDU)) forcoordinated communications between the second AP one or more STAs of thesecond AP during a second portion of the transmission opportunity. Thesecond AP may transmit a scheduling indicator, which may be received atthe first AP and by the one or more STAs of the second AP. The first APmay, in some cases, then transmit an indication of a start of the secondportion of the transmission opportunity (e.g., via a MAP PPDU or a HE TBPPDU), and both the first AP and the second AP may communicate with oneor more associated STAs during the second portion of the TxOP. Thecommunications during the second portion of the TxOP may include OFDMAcommunications in which multiple APs concurrently communicate withmultiple STAs.

In various aspects of the present disclosure, multi-AP coordination forconcurrent transmissions within a portion of a TxOP may be used in anunmanaged network (e.g., a network without backhaul links between APs,without a central controller or schedule, and without long termsynchronization), such that a TxOP owner AP may schedule one or moreneighboring APs, and the multiple APs may participate in multi-APcoordinated communications. Coordinated communications may include, forexample, coordinated multi-AP OFDMA, where subchannels of a wirelessbandwidth used by each AP are orthogonal to each other, or coordinatedreuse, where multiple APs may participate in simultaneous uplink anddownlink transmissions with relatively low interference to each other.

Techniques such as discussed herein may provide a TxOP owner AP, forexample, with an ability to obtain a longer TxOP, an increased accesspriority, or combinations thereof. Such TxOP duration and accesspriority, for example, may be based on a number of overlapping basicservice set (OBSS) APs participating in the coordinated transmissions.Further, such techniques may improve system throughput, increasespectral efficiency by more fully using one or more availablesubchannels within a wireless bandwidth, enhanced interferencemanagement by allowing coordinated concurrent transmissions inorthogonalized wireless resources, and efficient implementation withouta need for backhaul coordination among APs.

Additional aspects of the disclosure are initially described in thecontext of a wireless communications system. Various examples ofmulti-AP communications and related PPDUs are then described inaccordance with some multi-AP communications techniques. Aspects of thedisclosure are further illustrated by and described with reference toapparatus diagrams, system diagrams, and flowcharts that relate tomulti-access point scheduling in wireless local area networks.

In some aspects, wireless communication systems may be configured tosupport multi-user (MU) transmissions where multiple access points(AP(s)) perform wireless communications with their associated wirelessstations during a transmission opportunity (TxOP). For example, a firstAP (e.g., a master AP) may obtain or otherwise secure access to achannel for the TxOP. The channel/TxOP may have available resourcesbeyond what the master AP needs to perform its wireless communications.Accordingly, the master AP may generally transmit or otherwise signal anindication to second AP(s) (e.g., slave or neighboring AP(s)) that theresources are available for use during the TxOP. The second AP(s) maygenerally perform wireless communications using the unused resourcesduring the TxOP. However, conventional techniques that support a MUtransmission are rudimentary at best. For example, sharing of the unusedresources is typically limited to AP(s) within a basic service set (BSS)and/or may not provide for effective utilization of the availableresources, e.g., may not provide an efficient mechanism for the masterAP to dynamically allocate the available resources between the slaveAP(s).

Aspects of the disclosure are initially described in the context of awireless communication system. In some aspects, the described techniquesintroduce a phase approach to allow AP(s) (within a basic service set(BSS) and/or associated with different BSSs) to perform a coordinated aMU transmission using dynamically allocated resources. For example, amaster AP (e.g., the first AP) may obtain or otherwise secure access toa shared or unlicensed radio frequency spectrum band for a TxOP. Forexample, the master AP may perform a listen-before-talk (LBT) procedureto obtain access to the channel for the TxOP. In some aspects, thechannel may be a wideband channel and/or the TxOP may have a durationsuch that the available resources for use during the TxOP are more thanthe master AP needs.

Accordingly, in a first stage (or stage 1) the master AP may transmit orotherwise provide an indication of a request to participate (orinvitation to participate) in the MU transmission during the TxOP to itsneighboring AP(s). In a second stage (or stage 2), one or more of theneighboring AP(s) (e.g., one or more second AP(s), which may also bereferred to as slave AP(s)) may receive the request to participate anddetermine that they have communications to exchange with theirassociated wireless station(s). Each of the one or more neighboringAP(s) may determine that, based on the data being available forcommunication, what resources are needed for them to communicate thedata during the TxOP. Accordingly, each of the one or more neighboringAP(s) may respond by transmitting or otherwise providing an indicationof an intent to participate in the MU transmission to the master AP.Generally, the indication of intent to participate may also carry orotherwise convey an indication of the resources that the neighboring APis requesting for the MU transmission. In a third stage (or stage 3),the master AP may transmit or otherwise provide an indication of atrigger signal that carries or otherwise conveys an indication resourcesfor the neighboring AP(s) to use during the MU transmission (e.g., aresource grant or allocation). During a fourth stage (or stage 4), themaster AP and the neighboring AP(s) may participate in the MUtransmission with their respective wireless stations.

Aspects of the disclosure are further illustrated by and described withreference to apparatus diagrams, system diagrams, and flowcharts thatrelate to protocols for multi-AP coordinated MU transmissions

FIG. 1 illustrates a wireless local area network (WLAN) 100 (also knownas a Wi-Fi network) configured in accordance with various aspects of thepresent disclosure. The WLAN 100 may include an AP 105 and multipleassociated STAs 115 that may communicate via wireless links 120. STAs115 may represent devices such as mobile stations, personal digitalassistant (PDAs), other handheld devices, netbooks, notebook computers,tablet computers, laptops, display devices (e.g., TVs, computermonitors, etc.), printers, etc. The AP 105 and the associated stations115 may represent a basis service set (BSS) or an extended service set(ESS). The various STAs 115 in the network are able to communicate withone another through the AP 105. Also shown is a coverage area 110 of theAP 105, which may represent a BSA of the WLAN 100. An extended networkstation (not shown) associated with the WLAN 100 may be connected to awired or wireless distribution system that may allow multiple APs 105 tobe connected in an ESS. In some aspects as discussed herein, AP 105 maycoordinate with one or more neighboring APs to provide coordinatedcommunications during a TxOP.

Although not shown in FIG. 1, a STA 115 may be located in theintersection of more than one coverage area 110 and may associate withmore than one AP 105. A single AP 105 and an associated set of STAs 115may be referred to as a BSS. An ESS is a set of connected BSSs. Adistribution system (not shown) may be used to connect APs 105 in anESS. In some cases, the coverage area 110 of an AP 105 may be dividedinto sectors (also not shown). The WLAN 100 may include APs 105 ofdifferent types (e.g., metropolitan area, home network, etc.), withvarying and overlapping coverage areas 110. Two STAs 115 may alsocommunicate directly via a direct wireless link 125 regardless ofwhether both STAs 115 are in the same coverage area 110. Examples ofdirect wireless links 125 may include Wi-Fi Direct connections, Wi-FiTunneled Direct Link Setup (TDLS) links, and other group connections.STAs 115 and APs 105 may communicate according to the WLAN radio andbaseband protocol for physical and MAC layers from IEEE 802.11 andversions including, but not limited to, 802.11b, 802.11g, 802.11a,802.11n, 802.11ac, 802.11ad, 802.11ah, 802.11ax, etc. In otherimplementations, peer-to-peer connections or ad hoc networks may beimplemented within WLAN 100.

Some types of STAs 115 may provide for automated communication.Automated wireless devices may include those implementinginternet-of-things (IoT) communication, Machine-to-Machine (M2M)communication, or machine type communication (MTC). IoT, M2M or MTC mayrefer to data communication technologies that allow devices tocommunicate without human intervention. For example, IoT, M2M or MTC mayrefer to communications from STAs 115 that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application.

Some of STAs 115 may be MTC devices, such as MTC devices designed tocollect information or enable automated behavior of machines. Examplesof applications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging. An MTCdevice may operate using half-duplex (one-way) communications at areduced peak rate. MTC devices may also be configured to enter a powersaving “deep sleep” mode when not engaging in active communications.

WLAN 100 may support beamformed transmissions. As an example, AP 105 mayuse multiple antennas or antenna arrays to conduct beamformingoperations for directional communications with a STA 115. Beamforming(which may also be referred to as spatial filtering or directionaltransmission) is a signal processing technique that may be used at atransmitter (for example, AP 105) to shape or steer an overall antennabeam in the direction of a target receiver (for example, a STA 115).Beamforming may be achieved by combining elements in an antenna array insuch a way that transmitted signals at particular angles experienceconstructive interference while others experience destructiveinterference. In some cases, the ways in which the elements of theantenna array are combined at the transmitter may depend on channelstate information (CSI) associated with the channels over which the AP105 may communicate with the STA 115. That is, based on this CSI, the AP105 may appropriately weight the transmissions from each antenna (forexample, or antenna port) such that the desired beamforming effects areachieved. In some cases, these weights may be determined beforebeamforming can be employed. For example, the transmitter (for example,the AP 105) may transmit one or more sounding packets to the receiver inorder to determine CSI.

WLAN 100 may further support multiple-input, multiple-output (MIMO)wireless systems. Such systems may use a transmission scheme between atransmitter (for example, AP 105) and a receiver (for example, a STA115), where both transmitter and receiver are equipped with multipleantennas. For example, AP 105 may have an antenna array with a number ofrows and columns of antenna ports that the AP 105 may use forbeamforming in its communication with a STA 115. Signals may betransmitted multiple times in different directions (for example, eachtransmission may be beamformed differently). The receiver (for example,STA 115) may try multiple beams (for example, antenna subarrays) whilereceiving the signals.

WLAN protocol data units (PDUs) may be transmitted over a radiofrequency spectrum band, which in some examples may include multiplesub-bands or frequency channels. In some cases, the radio frequencyspectrum band may have a bandwidth of 80 MHz, and each of the sub-bandsor channels may have a bandwidth of 20 MHz. Transmissions to and fromSTAB 115 and APs 105 typically include control information within aheader that is transmitted prior to data transmissions. The informationprovided in a header is used by a receiving device to decode thesubsequent data. A legacy WLAN preamble may include legacy shorttraining field (STF) (L-STF) information, legacy LTF (L-LTF)information, and legacy signaling (L-SIG) information. The legacypreamble may be used for packet detection, automatic gain control andchannel estimation, among other uses. The legacy preamble may also beused to maintain compatibility with legacy devices.

In some cases, AP 105 may coordinate one or more transmissions with oneor more neighboring APs. In some cases, the AP 105 may gain channelaccess for a TxOP, and may coordinate with at least a second AP to allowboth the AP 105 and the second AP to transmit and receive wirelesscommunications during the TxOP. In some cases, PPDU for multi-APcoordination is transmitted by the AP 105 to the one or more other APs,which may carry information related to scheduling and transmissionresources for coordination of concurrent transmissions by multiple APs.Additionally or alternatively, OFDMA techniques may be used by AP 105and one or more other APs for concurrent communicate with one or moreassociated STAs 115 using one or more wireless channels.

In some cases, a STA 115 (or an AP 105) may be detectable by a centralAP 105, but not by other STAs 115 in the coverage area 110 of thecentral AP 105. For example, one STA 115 may be at one end of thecoverage area 110 of the central AP 105 while another STA 115 may be atthe other end. Thus, both STAs 115 may communicate with the AP 105, butmay not receive the transmissions of the other. This may result incolliding transmissions for the two STAs 115 in a contention basedenvironment (e.g., CSMA/CA) because the STAs 115 may not refrain fromtransmitting on top of each other. A STA 115 whose transmissions are notidentifiable, but that is within the same coverage area 110 may be knownas a hidden node. CSMA/CA may be supplemented by the exchange of an RTSpacket transmitted by a sending STA 115 (or AP 105) and a CTS packettransmitted by the receiving STA 115 (or AP 105). This may alert otherdevices within range of the sender and receiver not to transmit for theduration of the primary transmission. Thus, RTS/CTS may help mitigate ahidden node problem.

In some aspects, an AP 105 (e.g., a first AP) may transmit, to a secondAP 105 and during a first portion of a TxOP, a request to participate ina multi-user transmission during a second portion of the TxOP. The AP105 may receive, from the second AP 105 and during the first portion ofthe TxOP, an indication of intent to participate in the multi-usertransmission during the second portion of the TxOP, the indication ofintent including a resource request of the second AP 105 forparticipation in the multi-user transmission. The AP 105 may transmit,during an initial period of the second portion of the TxOP, a triggersignal to the second AP 105 indicating a set of one or more resourcesfor the second AP 105 during the multi-user transmission. The AP 105 mayparticipate, in conjunction with the second AP 105 and during the secondportion of the TxOP, in the multi-user transmission.

In some aspects, an AP 105 (e.g., a second AP) may receive, from a firstAP 105 and during a first portion of a TxOP, a request to participate ina multi-user transmission during a second portion of the TxOP. The AP105 may transmit, to the first AP 105 and during the first portion ofthe TxOP, an indication of intent to participate in the multi-usertransmission during the second portion of the TxOP, the indication ofintent including a resource request of the second AP 105 forparticipation in the multi-user transmission. The AP 105 may receive,during an initial period of the second portion of the TxOP, a triggersignal from the first AP 105 indicating a set of one or more resourcesfor the second AP 105 during the multi-user transmission. The AP 105 mayparticipate, in conjunction with the first AP 105 and during the secondportion of the TxOP, in the multi-user transmission.

FIG. 2 illustrates an example of a WLAN 200 that supports multi-accesspoint scheduling in wireless local area networks in accordance withaspects of the present disclosure. In some examples, WLAN 200 mayimplement aspects of wireless communication system 100. In this example,a first AP 105-a may have multiple neighboring APs 105, including asecond AP 105-b and a third AP 105-c. Further, a number of STAs 115 maybe present, including a first STA 115-a that may be associated with thefirst AP 105-a via wireless link 120-a, a second STA 115-b that may beassociated with the second AP 105-b via wireless link 120-b, and a thirdSTA 115-c that may be associated with the third STA 115-c via wirelesslink 120-c.

In this example, the first AP 105-a may also have a wireless link 205-awith the second AP 105-b, and a wireless link 205-b with the third AP105-c. In some cases, the first AP 105-a may gain channel access for aTxOP, and may coordinate with the second AP 105-b and the third AP 105-cto allow the first AP 105-a, the second AP 105-b, and the third AP 105-cto transmit and receive wireless communications during the TxOP. Thefirst AP 105-a, upon gaining channel access (e.g., following asuccessful contention-based channel access procedure), may initiate ascheduling phase with the second AP 105-b and the third AP 105-c toschedule of resources within the TxOP for communications by each AP 105.

In some cases, the first AP 105-a may transmit, during a first portionof the TxOP, a first resource assignment (e.g., using a MAP PPDU or a HETB PPDU) for coordinated communications between the second AP 105-b andthird AP 105-c one or more associated STAs 115 during a second portionof the TxOP. The second AP 105-b and third AP 105-c may transmit ascheduling indicator to their associated STAs 115, which may be receivedat the first AP 105-a. The first AP 105-a may, in some cases, thentransmit an indication of a start of the second portion of the TxOP(e.g., via a MAP PPDU or a HE TB PPDU), and the first AP 105-a, thesecond AP 105-b, and the third AP 105-c may communicate with the STAs115 during the second portion of the TxOP. Such a technique, andcommunications between the different APs 105, is discussed in furtherdetail with reference to the examples of FIGS. 3 through 5.

FIG. 3 illustrates an example of multi-AP coordination 300 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some examples,multi-AP coordination 300 may implement aspects of wirelesscommunication system 100 or 200. In this example, first AP 105-a, secondAP 105-b, and third AP 105-c may perform coordinated transmissions.

Initially, each of the APs 105 may contend for access to a wirelesschannel during a contention/countdown window 305. In some cases, thefirst AP 105-a may be the first to contend for channel access (e.g.,according to an EDCA contention-based channel access procedure), and maywin the medium. In some cases, one or more of the other APs 105 mayattempt to access the channel before the first AP 105-a wins contention,but may not win contention, such as due to sending that anothertransmitter is using the wireless channel.

Upon winning the contention-based channel access procedure, the first AP105-a may initiate a multi-AP scheduling phase during a first portion ofthe TxOP 307. In the example of FIG. 3, the first AP 105-a may transmita scheduling trigger such as a MAP-Sch-Trigger 310, which may bereceived by each of the second AP 105-b and the third AP 105-c. TheMAP-Sch-Trigger 310 may be a MAP PPDU that the first AP 105-a transmitsto initiate scheduling multi-AP communications. The second AP 105-b andthe third AP 105-c may transmit one or more multi-AP scheduling 315communications that may be received by one or more associated STAs, andthat are also received by the first AP 105-a. The first AP 105-a, basedon transmissions of the second AP 105-b and the third AP 105-c, maydetermine wireless resources (e.g., frequency resources, time resources,or combinations thereof) that will be used for multi-AP communicationsin a second portion of the TxOP 317. The first AP 105-a may thentransmit a MAP-trigger 320 in the second portion of the TxOP 317, whichmay indicate to each of the other APs 105 that multi-AP coordinatedtransmission 325 may commence. In some cases, multi-AP coordinatedtransmission 325 may include transmissions from all participating BSSssimultaneously within the second portion of the TxOP 317. Resourceswithin the multi-AP coordinated transmission 325 may be allocated, asindicated above, based on time resources, frequency resources, or usingcoordinated OFDMA using orthogonal channels.

FIG. 4 illustrates an example of a multi-AP scheduling technique 400that supports multi-access point scheduling in wireless local areanetworks in accordance with aspects of the present disclosure. In someexamples, multi-AP scheduling technique 400 may implement aspects ofwireless communication system 100 or 200. In this example, first AP105-a, second AP 105-b, and third AP 105-c may perform coordinatedtransmissions.

Initially, each of the APs 105 may contend for access to a wirelesschannel during a contention/countdown window 405. In some cases, thefirst AP 105-a may be the first to contend for channel access and maywin the medium. In some cases, similarly as discussed above, one or moreof the other APs 105 may attempt to access the channel before the firstAP 105-a wins contention, but may not win contention. Upon winning thecontention-based channel access procedure, the first AP 105-a maytransmit a scheduling trigger such as a MAP-Sch-Trigger 410, which maybe received by the second AP 105-b. The MAP-Sch-Trigger 410 may be a MAPPPDU that the first AP 105-a transmits to each neighboring AP 105, oneat a time, to initiate scheduling of multi-AP communications. The secondAP 105-b, in this case, may transmit a scheduling indication 415 to itsassociated STAs, that may also be received by the first AP 105-a. Thefirst AP 105-a may then send a second MAP-Sch-Trigger 420, which may bereceived by the third AP 105-c. The third AP 105-c, in this case, maytransmit a scheduling indication 425 to its associated STAs, that mayalso be received by the first AP 105-a. The first AP 105-a, based on thescheduling indications 415 and 425, may determine resources fortransmissions of each AP 105, and may transmit a MAP-Trigger 430 toinitiate the multi-AP coordinated transmissions 435.

In this example, because only one AP 105 is targeted at any time by theMAP-Sch-trigger 410 or 420, the scheduling indications 415 and 425 willnot interfere with each other. In some cases, the scheduling indications415 and 425 may include a scheduling indication (SI) frame transmissionthat is sent by each AP 105 to its associated STAs (e.g., in a SU PPDUformat). The first AP 105-1, as the TXOP Owner AP, monitors SI framesand may determine when to poll the next-in-line AP. Such a techniqueprovides relatively simple scheduling for multi-AP communications,although time resources associated with multiple APs are consumed.

FIG. 5 illustrates an example of a concurrent scheduling for multipleAPs 500 that supports multi-access point scheduling in wireless localarea networks in accordance with aspects of the present disclosure. Insome examples, concurrent scheduling for multiple APs 500 may implementaspects of wireless communication system 100 or 200. In this example,first AP 105-a, second AP 105-b, and third AP 105-c may performcoordinated transmissions in which concurrent scheduling of multiple APs105 may be implemented.

Similarly as discussed above, in the example of FIG. 5, each of the APs105 may contend for access to a wireless channel during acontention/countdown window 505. In some cases, the first AP 105-a maybe the first to contend for channel access and may win the medium. Insome cases, similarly as discussed above, one or more of the other APs105 may attempt to access the channel before the first AP 105-a winscontention, but may not win contention. Upon winning thecontention-based channel access procedure, the first AP 105-a maytransmit a scheduling trigger such as a MAP-Sch-Trigger 510, which maybe received by the second AP 105-b and the third AP 105-b. TheMAP-Sch-Trigger 510 may be a MAP PPDU that the first AP 105-a transmitsto each neighboring AP 105 to initiate scheduling of multi-APcommunications. The second AP 105-b and the third AP 105-c, in thiscase, may concurrently transmit a scheduling indication. In some cases,the scheduling indication may be provided in a MAP-PPDU from each of thesecond AP 105-b and third AP 105-c in which a subchannel used fortransmission of a SI frame may be derived from the MAP-Sch-Trigger 510.In the example of FIG. 5, the second AP 105-b may transmit a schedulingindication that includes a preamble 515-a, and a SI-frame 520 thatoccupies a first sub-channel of multiple available subchannels (e.g., afirst 20 MHz channel of multiple available 20 MHz channels). In thisexample, two subchannels are illustrated, and the second AP 105-b has anunused second subchannel 525. Similarly, the third AP 105-c may transmita scheduling indication that includes a preamble 515-b, and a SI-frame530 that occupies the second subchannel, leaving the first subchannel asan unused subchannel 535. Thus, the different SI frames 520 and 530 willnot interfere with each other, and can be concurrently transmitted,which may more efficiently use time and frequency resources.

In some cases, the MAP-Sch-Trigger 510 may be transmitted by the firstAP 105-a, as the TxOP owner AP, to each of the other neighboring APs105, and may trigger the other APs 105 to transmit the SI Frames 520 and530. In some cases, the preambles 515 transmitted by each AP 105 includeand AP identifier (e.g., expressed using short BSSID or Color code, orspecial associated ID (AID)) and an indication of a subchannel of the SIframe. In some cases, the preamble 515 and SI frames 520 and 530 may beformatted in a MAP-PPDU. Associated STAs of the different APs 105 may,in some cases, determine the subchannel used by its AP 105 by decodingthe preamble 515, and each STA in the associated BSS may tune to thesubchannel assigned for that AP 105, and all per-STA information may becarried within the SI frame (e.g., MAC information).

The first AP 105-a, based on the SI frames 520 and 530, may determineresources for transmissions of each AP 105, and may transmit aMAP-Trigger 540 to initiate the multi-AP coordinated transmissions 545.

As indicated above, in some cases a MAP PPDU may be defined thatprovides multi-AP coordination and scheduling information. Variousdifferent formats may be used for the MAP-PPDU. In some cases, multipleAPs 105 may respond with the MAP PPDU after the reception of a Triggerframe sent by the TXOP Owner, namely the first AP 105-a in the aboveexamples. The response from the other APs 105 may have frequency/timecorrection as in HE trigger-based (TB) PPDUs. The preambles 515 sent byall of the responding APs 150 may be the same to provide that there isno collision, and the preambles 515 may be transmitted using the entirebandwidth of the PPDU. STAs that are associated with each of the APs 105may derive the sub-channel in which its associated AP sends its PSDUs,and in some cases the preamble 515 of the MAP PPDU may carry a BSSidentifier, and a corresponding mapping to the subchannel. Further, STAsassociated to all responding APs 105 may be expected to be on the TXOPOwner's primary channel. In such cases, the MAP-Sch-Trigger 510 mayindicate the subchannel for each neighboring AP 105, and may ensure thatthe common portions of the preamble 515 generated by the APs 105 areidentical. In some cases, the common preamble 515 may be signaledexplicitly, or derived implicitly from the MAP-Sch-Trigger 510.

FIG. 6A illustrates one example of a MAP PPDU 600-a that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some examples,multi-AP physical protocol data unit 600-a may implement aspects ofwireless communication system 100 or 200. In this example, the MAP PPDU600 may reuse a format of the defined HE MU PPDU, which may include aL-STF field 601, a L-LTF field 602, a L-SIG field 603, a RL-SIG field604, a HE-SIG-A field 605, a HE-SIG-B field 606, HE-STF field 607, oneor more HE-LTF fields 608 through 609, a data portion 610, and packetextension (PE) field 611. In this example, the MAP PPDU 600-a may usethe STAID fields of HE-SIG-B field 606 to carry an identifier of eachneighboring AP (e.g., as determined from a short BSSID, a color-code, ora special AID value of the APs).

In some case, STA-ID field of HE-SIG B 606 may carry the AID of a STA.In some cases, for the purpose of coordinated re-use, the STA-ID may beoverloaded to carry a BSS identifier of the AP, such that STAsassociated with that BSS decode the corresponding resource unit. In somecases, one or more fields in the HE-SIG-A 605 may indicate if HE-SIG-Bfield 606 has an alternate interpretation. For example, by setting theBSS Color field in SIG-A to a special value (e.g., color=63). In otherexamples, UL Flag in SIG-A may be used (which in legacy system may beset to 1 when STA UL to AP, set to 0 when AP DL to STA, and in bothcases the STA-ID may be set to the AID of intended STA, thus atransmitting AP will not set UL to 1), and for the purpose coordinatedre-use, APs may set UL to 1 in the MU PPDU to indicates that STA-IDcarries BSS identifiers. The BSS identifier may be set to, for example,a random AID value picked by each AP and advertised in the AP's beaconto inform associated STAs, derived based on the BSSID of the AP (e.g.,STAs derive by applying a hash function to the BSSID), or a BSS colorindication.

FIG. 6B illustrates another example of a MAP PPDU 600-b that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some examples,multi-AP physical protocol data unit 600-b may implement aspects ofwireless communication system 100 or 200. In this example, the MAP PPDU600-b may modify a format of the defined HE TB PPDU, which may include aL-STF field 612, a L-LTF field 613, a L-SIG field 614, a RL-SIG field615, a HE-SIG-A field 616, a HE-STF field 617, one or more HE-LTF fields618 through 619, a data portion 620, and packet extension (PE) field621. In this example, the MAP PPDU 600-b may have a new field defined(e.g., HE-SIG-C) to the preamble to carry the mapping of AP identifierto the subchannel. In other examples, the MAP PPDU 600-b may reuse theHE TB PPDU by reusing certain reserved/unused fields. For example,Spatial Reuse fields of the HE-SIG-A may be used for carrying the APidentifier and subchannel mapping. In further examples, a new EHT PPDUformat may be defined to that provides information as discussed for MAPPPDUs. For example, SR bits in the HE-SIG-A field 616 may be used toprovide coordinated transmission information. In such cases, 25+1 of25+1 bits are available, and may be used to carry information such as anindication of a special interpretation of SIG-A (1-bit) (e.g., bit 23)BSS Color (e.g., 6-bits per BSS), or sub-channels available for re-use(16-bits, with 1 bit for each 20 MHz of a 320 MHz BW).

In some cases, to ensure that HE-SIG-A and HE-SIG-B fields sent by allAPs are the same, the TXOP Owner AP may sends the contents of the HESIG-A, HE-SIG-BA to the neighboring APs implicitly or explicitly, andmay set the BSS color in HE-SIG-A to a single value (color 0, forexample).

FIG. 6C illustrates an example of a MAP PPDU 600-c that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some cases,various MAP OFDMA processes such as those implementing MAP PPDU 600-cmay use a pre-setup packet. A pre-setup packet may be used to directSTAs to a content channel (e.g., a primary 20 MHz (P20) channel)associated with a serving AP. A MAP PPDU such as MAP PPDU 600-c may betransmitted after the pre-setup packet. In some examples, multi-APphysical protocol data unit 600-c may be transmitted after the pre-setuppacket. In some examples, MAP PPDU 600-c may be similar to preamblepuncturing, with additional aspects or differences related to tone plan.In one implementation, if a MAP PPDU 600-c crosses a channel boundary(e.g., a 20 MHz channel), boundary RUs may be voided. In anotherimplementation, such boundary RUs may be used for data (e.g., the RUsmay not be punctured). Such coordination for using boundary RUs for datamay in some cases minimize signaling interference.

In some examples, all APs may transmit the same content using MAP PPDUformat, and since all fields may be duplicated according to a giveninterval (e.g., a frequency interval, such as every 20 MHz), a preamblemay be drawn for the given interval (e.g., a preamble is included for 20MHz). In some cases, a channel used to signal a preamble associated withone AP may be different than a channel used to transmit data. Forexample, signaling of one AP in a preamble may be located in a different20 MHz channel than data transmitted.

In this example, MAP PPDU format 600-c may include a L-STF field 622, aL-LTF field 623, a L-SIG field 624, a RL-SIG field 625, a Hybrid SIGfield 626, an EHT-SIG-A field 627, and an EHT-SIG-B field. In MAP PPDUformat 600-c, EHT-SIG-A and EHT-SIG-B common may be separately encodedfor the MAP PPDU 600-c (e.g., EHT-SIG-A field 627 is a separate fieldfrom EHT-SIG-B field 628). Hybrid SIG in some cases may also be referredto as Pre-SIG or a Pre-SIG field. Hybrid SIG or Pre-SIG may carryinformation to interpret EHT PPDUs, which may include versionindependent fields and version dependent fields. In some cases HybridSIG field 626 may use a unified BSS color to identify a group of APsparticipating in MAP OFDMA. For example, Hybrid SIG field 626 may setthe BSS color to a single value. In addition, the Hybrid SIG field 626or EHT-SIG-A field 627 may include an indicator (e.g., a one bitindicator) that may indicate a MAP OFDMA pre-setup packet. In somecases, the indicator included in Hybrid SIG field 626 or EHT-SIG-A field627 may enable a per-AP information field.

The per-AP information field may in some examples repurpose certainreserved or unused fields. For example, common RU allocation table forSTAs may be repurposed for a sub-band allocation table for APs in theHE-SIG-B. The RU allocation table may in some cases be used for APs toindicate which multiples of a certain frequency within a channel (e.g.,20 MHz) may be occupied by each corresponding AP. In some other cases,the SIG-B per-user field for STAs is repurposed as a per-AP field forAPs. In some of the described fields, a STA ID may be repurposed forvarious other parameters, including AP ID or BSS color.

In some cases, to ensure that EHT-SIG-A and EHT-SIG-B fields sent by allAPs are the same, the TXOP Owner AP may send the contents of the HESIG-A and HE-SIG-B to the neighboring APs implicitly or explicitly, andmay set the BSS color in HE-SIG-A to a single value.

As discussed herein, different channels may be used for signaling of oneAP using a preamble and for transmitting data. Accordingly, in somecases, MAP OFDMA information may be indicated prior to EHT-SIG-B userfield 628. In one example, a new field may indicate the MAP OFDMA dataPPDU. In another example, a compression field associated with EHT-SIG-Bmay be expanded (e.g., to two bits), where at least one bit may be usedto indicate MAP OFDMA. In addition to the indication of MAP OFDMA, anallocation table for RUs (e.g., associated with puncturing) may be usedfor MAP OFDMA. A given RU allocation scheme be associated with a commonvalue, and the RU allocation may include RUs which had crossed a channelboundary (e.g., RUs which would have otherwise been voided, for example,in a puncturing scenario).

FIG. 6D illustrates an example of a MAP PPDU 600-d that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some cases,various MAP OFDMA processes such as those implementing MAP PPDU 600-dmay use a pre-setup packet. A pre-setup packet may be used to directSTAs to a content channel (e.g., a primary 20 MHz (P20) channel)associated with a serving AP. A MAP PPDU such as MAP PPDU 600-d may betransmitted after the pre-setup packet. In some examples, multi-APphysical protocol data unit 600-d may be transmitted after the pre-setuppacket, and may implement aspects of wireless communication system 100or 200. In some examples, MAP PPDU 600-c may be similar to preamblepuncturing, with additional aspects or differences related to tone plan.In one implementation, if a MAP PPDU 600-c crosses a channel boundary(e.g., a 20 MHz channel), boundary RUs may be voided. In anotherimplementation, such boundary RUs may be used for data (e.g., the RUsmay not be punctured). Such coordination for using boundary RUs for datamay in some cases minimize signaling interference.

In further examples, all APs may transmit the same content using MAPPPDU format, and since all fields may be duplicated according to a giveninterval (e.g., a frequency interval, such as every 20 MHz), a preamblemay be drawn for the given interval (e.g., a preamble is included for 20MHz). In some cases, a channel used to signal a preamble associated withone AP may be different than a channel used to transmit data. Forexample, signaling of one AP in a preamble may be located in a different20 MHz channel than data transmitted.

In this example, MAP PPDU format 600-d may include a L-STF field 629, aL-LTF field 630, a L-SIG field 631, a RL-SIG field 632, a Hybrid SIGfield 633, and a combination EHT-SIG-A and EHT-SIG-B field 634. In thisexample, EHT-SIG-A and EHT-SIG-B common may be jointly encoded for theMAP PPDU 600-d (e.g., EHT-SIG-A field EHT-SIG-B are part of one commonfield 634). Hybrid SIG in some cases may also be referred to as Pre-SIGor a Pre-SIG field. Hybrid SIG or Pre-SIG may carry information tointerpret EHT PPDUs, which may include version independent fields andversion dependent fields. In some cases, Hybrid SIG may use a unifiedBSS color to identify a group of APs participating in MAP OFDMA. Forexample, Hybrid SIG field 633 may set the BSS color to a single value.In addition, the Hybrid SIG field 633 or combination EHT-SIG-A andEHT-SIG-B field 634 may include an indicator (e.g., a one bit indicator)that may indicate a MAP OFDMA pre-setup packet. In some cases, theindicator included Hybrid SIG field 633 or combination EHT-SIG-A andEHT-SIG-B field 634 may enable a per-AP information field.

The per-AP information field may in some examples repurpose certainreserved/unused fields. For example, common RU allocation table for STAsmay be repurposed for a sub-band allocation table for APs in theHE-SIG-B. The RU allocation table may in some cases be used for APs toindicate which multiples of a certain frequency within a channel (e.g.,20 MHz) may be occupied by each corresponding AP. In some other cases,the SIG-B per-user field for STAs is repurposed as a per-AP field forAPs. In some of the described fields, a STA ID may be repurposed forvarious other parameters, including AP ID or BSS color.

In some cases, to ensure that EHT-SIG-A and EHT-SIG-B field sent by allAPs are the same, the TXOP Owner AP may sends the contents of the HESIG-A and HE-SIG-B to the neighboring APs implicitly or explicitly, andmay set the BSS color to a single value.

As discussed herein, different channels may be used for signaling of oneAP using a preamble and for transmitting data. Accordingly, in somecases, MAP OFDMA information may be indicated prior to EHT-SIG-A andEHT-SIG-B user field 634. In one example, a new field may indicate theMAP OFDMA data PPDU. In another example, a compression field associatedwith EHT-SIG-A and EHT-SIG-B may be expanded (e.g., to two bits), whereat least one bit may be used to indicate MAP OFDMA. In addition to theindication of MAP OFDMA, an allocation table for RUs (e.g., associatedwith puncturing) may be used for MAP OFDMA. A given RU allocation schemebe associated with a common value, and the RU allocation may include RUswhich had crossed a channel boundary (e.g., RUs which would haveotherwise been voided, for example, in a puncturing scenario).

FIG. 6E illustrates an example of a MAP PPDU 600-e that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some cases,various MAP OFDMA processes such as those implementing MAP PPDU 600-emay use a pre-setup packet. A pre-setup packet may be used to directSTAs to a content channel (e.g., a primary 20 MHz (P20) channel)associated with a serving AP. A MAP PPDU such as MAP PPDU 600-e may betransmitted after the pre-setup packet. In some examples, MAP PPDU 600-emay implement aspects of wireless communication system 100 or 200. Infurther examples, all APs may transmit the same content using MAP PPDUformat, and since all fields may be duplicated according to a giveninterval (e.g., a frequency interval, such as every 20 MHz), a preamblemay be drawn for the given interval (e.g., a preamble is included for 20MHz).

In this example, MAP PPDU format 600-e may include a L-STF field 635, aL-LTF field 636, a L-SIG field 637, a RL-SIG field 638, a Hybrid SIGfield 639, EHT-SIG-A field 640 and a EHT-SIG-C field 641. MAP PPDUformat 600-e may in some cases not include an EHT-SIG-B field. In MAPPPDU format 600-e, the EHT-SIG-C field 641 may include per-AP fields toindicate information such an AP ID and a unified BSS color (e.g., toidentify a group of APs participating in MAP OFDMA). In some cases, SIGC field 641 may set the BSS color to a single value. In addition, theEHT-SIG-C field 641 may include an indications of which multiples of acertain frequency within a channel (e.g., 20 MHz) may be occupied byeach corresponding AP.

FIG. 6F illustrates an example of a MAP PPDU 600-f that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some cases,various MAP OFDMA processes such as those implementing MAP PPDU 600-fmay use a preamble section which may indicate, to a STA, contentchannels associated with a serving AP. MAP PPDU format 600-f may includea L-STF field 642, a L-LTF field 643, a L-SIG field 644, a RL-SIG field645, a Hybrid SIG field 646, EHT-SIG-A field 647, EHT-STF field 648,EHT-LTF field 649, EHT-SIG-B field 650, and EHT Data field 651.

In the example of MAP PPDU 600-f, a preamble may include L-STF field642, a L-LTF field 643, a L-SIG field 644, a RL-SIG field 645, a HybridSIG field 646, EHT-SIG-A field 647, EHT-STF field 648, EHT-LTF field 649(e.g., components positioned before EHT-SIG-B field 650). Accordingly,each AP may transmit the same content in the preamble for MAP PPDU600-f. In some examples, all APs may transmit the same content using MAPPPDU format 600-f, and all fields before EHT-SIG-B field 650 may beduplicated according to a given interval (e.g., a frequency interval,such as every 20 MHz). For example, fields may be duplicated as a 1st 20MHz, a 2nd 20 MHz, a 3rd 20 MHz, and a 4th 20 MHz. In addition, HybridSIG field 646 may use a unified BSS color to identify a group of APsparticipating in MAP OFDMA. For example, Hybrid SIG field 646 may setthe BSS color to a single value. In some cases, an indicator includedHybrid SIG field 646 or EHT-SIG-A field 647 may be used to indicate MAPOFDMA.

In addition, a per-AP information field may be used to identify sub-bandallocation. In some cases, the per-AP information field may beduplicated according to a set frequency interval, for example, every 20MHz. In the example of MAP PPDU structure 600-f, the per-AP informationfield may be included within a different field, such as EHT-SIG-A field647. In addition, the modulation and coding scheme (MCS) and/or dualcarrier modulation (DCM) of EHT-SIG-A field 647 may be indicated in anearlier field, such as in Hybrid SIG field 646.

The per-AP information field may in some cases include and AP ID or BSScolor to identify the BSS/AP. In addition, the per-AP information fieldmay include a N-bit channel bitmap associated with the total bandwidthof the PPDU (e.g., bandwidth N-times-B, 20 MHz). In some cases, thebitmap may be used to identify the sub-bands occupied by a BSS or AP.Further, the per-AP information field may include a bit field of one ortwo bits, which may indicate sub-band granularity among various sub-bandfrequency values (e.g., 20 MHz, 40 MHz, 80 MHZ, 160 MHz, etc.).

EHT-SIG-B field 650 and EHT Data field 651 may follow the preambleportions of MAP PPDU 600-f. Beginning at EHT-SIG-B field 650, each APmay occupy sub-bands for transmission, where each sub-band may be arepetition of a given frequency. For example, each sub-band may be amultiple of 20 MHz. Signaling and data of each AP may be carried in suchsub-bands as well (e.g., similar to a preamble puncturing scenario,where multiple 20 MHz channels are punctured, while other than an APsoccupied sub-bands). An AP may use a number of different contentchannels (e.g., [1,2,1,2], or [1,2,3,4] of full bandwidth, or separatecontent channels for every 160 MHz). In addition, the AP may utilize anRU allocation table related to preamble puncturing.

EHT-STF field 648 and EHT-LTF field 649 may be located before EHT-SIG-B650. In some cases, EHT-STF field 648 and EHT-LTF field 649 may includeautomatic gain control (AGC) settings in addition to channel estimateinformation that an AP may use before demodulating EHT-SIG-B field 650and EHT-Data field 651.

FIG. 6G illustrates an example of a MAP PPDU 600-g that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some cases,various MAP OFDMA processes such as those implementing MAP PPDU 600-gmay use a preamble section which may indicate, to a STA, contentchannels associated with a serving AP. MAP PPDU format 600-g may includea L-STF field 652, a L-LTF field 653, a L-SIG field 654, a RL-SIG field655, a Hybrid SIG field 656, EHT-SIG-A field 657, EHT-SIG-C field 658,EHT-STF field 659, EHT-LTF field 660, EHT-SIG-B field 661, and EHT Datafield 662.

In the example of MAP PPDU 600-g, a preamble may include L-STF field652, a L-LTF field 653, a L-SIG field 654, a RL-SIG field 655, a HybridSIG field 656, EHT-SIG-A field 657, EHT-SIG-C field 658, EHT-STF field659, EHT-LTF field 660 (e.g., components positioned before EHT-SIG-Bfield 661). Accordingly, each AP may transmit the same content in thepreamble for MAP PPDU 600-g. In some examples, all APs may transmit thesame content using MAP PPDU format 600-g, and all fields beforeEHT-SIG-B field 661 may be duplicated according to a given interval(e.g., a frequency interval, such as every 20 MHz). For example, fieldsmay be duplicated as a 1st 20 MHz, a 2nd 20 MHz, a 3rd 20 MHz, and a 4th20 MHz. In addition, Hybrid SIG field 656 may use a unified BSS color toidentify a group of APs participating in MAP OFDMA. For example, HybridSIG field 656 may set the BSS color to a single value. In some cases, anindicator included Hybrid SIG field 656 or EHT-SIG-A field 657 may beused to indicate MAP OFDMA.

In addition, a per-AP information field may be used to identify sub-bandallocation. In some cases, the per-AP information field may beduplicated according to a set frequency interval, for example, every 20MHz. In the example of MAP PPDU structure 600-f, the per-AP informationfield may be included within a different field, such as EHT-SIG-A field657. Additionally or alternatively, the per-AP information field may beincluded in the EHT-SIG-C field 658, which may be located betweenEHT-SIG-A field 657 and EHT-SIG-B field 661. In addition, the modulationand coding scheme (MCS) and/or dual carrier modulation (DCM) ofEHT-SIG-C field 658 may be indicated in an earlier field, such as inHybrid SIG field 656 or EHT-SIG-A field 657.

The per-AP information field may in some cases include and AP ID or BSScolor to identify the BSS/AP. In addition, the per-AP information fieldmay include a N-bit channel bitmap associated with the total bandwidthof the PPDU (e.g., bandwidth N-times-B, 20 MHz). In some cases, thebitmap may be used to identify the sub-bands occupied by a BSS or AP.Further, the per-AP information field may include a bit field of one ortwo bits, which may indicate sub-band granularity among various sub-bandfrequency values (e.g., 20 MHz, 40 MHz, 80 MHZ, 160 MHz, etc.).

EHT-SIG-B field 661 and EHT Data field 662 may follow the preambleportions of MAP PPDU 600-g. Beginning at EHT-SIG-B field 661, each APmay occupy sub-bands for transmission, where each sub-band may be arepetition of a given frequency. For example, each sub-band may be amultiple of 20 MHz. Signaling and data of each AP may be carried in suchsub-bands as well (e.g., similar to a preamble puncturing scenario,where multiple 20 MHz channels are punctured, while other than an APsoccupied sub-bands). An AP may use a number of different contentchannels (e.g., [1,2,1,2], or [1,2,3,4] of full bandwidth, or separatecontent channels for every 160 MHz). In addition, the AP may utilize anRU allocation table related to preamble puncturing.

EHT-STF field 659 and EHT-LTF field 660 may be located before EHT-SIG-B661. In some cases, EHT-STF field 659 and EHT-LTF field 660 may includeautomatic gain control (AGC) settings in addition to channel estimateinformation that an AP may use before demodulating EHT-SIG-B field 661and EHT-Data field 662.

FIG. 7A illustrates an example of a protocol sequence for downlinkorthogonal frequency division multiple access (OFDMA) 700 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some examples,protocol sequence for downlink orthogonal frequency division multipleaccess (OFDMA) 700 may implement aspects of wireless communicationsystem 100 or 200. In this example, first AP 105-a, second AP 105-b, andthird AP 105-c may perform coordinated transmissions in which concurrentscheduling of multiple APs 105 may be implemented.

Similarly as discussed above, in the example of FIG. 7A, each of the APs105 may contend for access to a wireless channel during acontention/countdown window 705. In some cases, the first AP 105-a maybe the first to contend for channel access and may win the medium. Insome cases, similarly as discussed above, one or more of the other APs105 may attempt to access the channel before the first AP 105-a winscontention, but may not win contention. Upon winning thecontention-based channel access procedure, the first AP 105-a maytransmit a scheduling trigger such as a MAP-Sch-Trigger 710, which maybe received by the second AP 105-b and the third AP 105-b. TheMAP-Sch-Trigger 710 may be a MAP PPDU that the first AP 105-a transmitsto each neighboring AP 105 to initiate scheduling of multi-APcommunications. The second AP 105-b and the third AP 105-c, in thiscase, may perform multi-AP scheduling 715, such as according to any oneof the examples discussed herein. The first AP 105-a, based on themulti-AP scheduling 715 may, may determine resources for transmissionsof each AP 105, and may transmit a MAP-Trigger 720 to initiate themulti-AP coordinated transmissions.

In this example, multi-AP coordinated transmission may use OFDMA toprovide concurrent transmissions of multiple APs 105 and STAs. In thisexample, the first AP 105-a may transmit preamble 725 that spans anumber of subchannels, and PSDU(s) 730 using a first subchannel (e.g., aprimary 20 MHz channel), while remaining subchannels are idle. Thesecond AP 105-b may transmit preamble 735 that spans a number ofsubchannels, and PSDU(s) 740 using a second subchannel (e.g., asecondary 20 MHz channel), while remaining subchannels are idle.Likewise, the third AP 105-c may transmit preamble 745 that spans anumber of subchannels, and PSDU(s) 750 using a third subchannel (e.g., asecondary 40 MHz channel), while remaining subchannels are idle.

In this example, the first AP 105-a, as the TXOP owner, may indicate thesub-channel for each neighboring AP 105. Such an indication may beprovided in MAP-Sch-Trigger 710, and the second AP 105-b and third AP105-c may use the allocated subchannel to serve their STAs. In somecases, the subchannel used for data communications may be different froma subchannel that is assigned to send an SI frame during Multi-APscheduling phase in examples that provide concurrent transmissions of SIframes. In some cases, each neighboring AP may select the STAs that willbe served during a coordinated OFDMA phase, and may provide anindication of the selected STAs using an SI frame (the first AP 105-amay not be aware of the list of selected STAs). In some examples, aspart of multi-AP scheduling 715, the second AP 105-b and third AP 105-cmay transmit SI frames to STAs that are selected to be served duringcoordinated OFDMA, and the assigned RU within the sub-channel that theAP is assigned by the first AP 105-a as the TxOP owner. In some cases,the first AP 105-a may assign the subchannel for coordinated OFDMAtransmissions using MAP-Sch-Trigger 710 frame.

In this example, coordinated OFDMA transmissions are initiated inresponse to the MAP-trigger 720. In some case, coordinated OFDMA may beindicated in the MAP-PPDU format or in the HE TB PPDU format in whichcase the information on scheduled STAs may be communicated duringMulti-AP scheduling 715 phase. The MAP-Trigger 720 may providescheduling information for coordinated OFDMA, which may includesub-channel assignment for each of the participating APs 105 for use intransmitting coordinated OFDMA communications. In some cases,sub-channel assignments may be provided in the MAP-scheduling-trigger710, and the assignments may carry over to the coordinated OFDMAcommunications. In other cases, the first AP 105-a may assign thesub-channel at the time of scheduling so that resources can be allocatedmore efficiently.

FIG. 7B illustrates another example of a protocol sequence for downlinkOFDMA 755 that supports multi-access point scheduling in wireless localarea networks in accordance with aspects of the present disclosure. Insome examples, protocol sequence for downlink OFDMA 755 may implementaspects of wireless communication system 100 or 200. In this example,similarly as with the example of FIG. 7A, first AP 105-a, second AP105-b, and third AP 105-c may perform coordinated transmissions in whichconcurrent scheduling of multiple APs 105 may be implemented.

In the example of FIG. 7B, each of the APs 105 may contend for access toa wireless channel during a contention/countdown window 757. In somecases, the first AP 105-a may be the first to contend for channel accessand may win the medium. In some cases, similarly as discussed above, oneor more of the other APs 105 may attempt to access the channel beforethe first AP 105-a wins contention, but may not win contention. Uponwinning the contention-based channel access procedure, in this example,the multi-AP scheduling step may be skipped, and the first AP 105-a maytransmit a MAP-Trigger 759 directly following contention, which mayindicate the mapping of AP identifiers to corresponding subchannel. Forexample, the MAP-Trigger 759 may provide scheduling information forcoordinated OFDMA, which may include sub-channel assignment for each ofthe participating APs 105 for use in transmitting coordinated OFDMAcommunications.

In the example of FIG. 7B, following MAP-Trigger 759, the first AP 105-amay initiate transmission of a MAP PPDUs following a SIFS after theMAP-Trigger 759, which may include a preamble 761 and PSDU(s) 763.Similarly, the second AP 105-b and third AP 105-c may transmitrespective preambles 765 and 769 followed by corresponding PSDU(s) 767and 771. Preambles 761-769 and PSDU(s) 763-771 may be transmitted fromeach AP 105 simultaneously, and such transmissions may start following aSIFS after MAP-Trigger 759. In this example, the first AP 105-a maytransmit preamble 761 that spans a number of subchannels, and PSDU(s)763 using a first subchannel (e.g., a primary 20 MHz channel), whileremaining subchannels are idle. The second AP 105-b may transmitpreamble 765 that spans a number of subchannels, and PSDU(s) 767 using asecond subchannel (e.g., a secondary 20 MHz channel), while remainingsubchannels are idle. Likewise, the third AP 105-c may transmit preamble769 that spans a number of subchannels, and PSDU(s) 771 using a thirdsubchannel (e.g., a secondary 40 MHz channel), while remainingsubchannels are idle. The preambles 761, 765, and 769 may include, insome cases, a common part and a per-AP part, as will be discussed inmore detail with respect to FIG. 7C.

FIG. 7C illustrates an example of MAP PPDUs 775 that supportmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some examples, MAPPPDUs 775 may implement aspects of wireless communication system 100 or200. In this example, a preamble 777 of each AP may include a commonpart 779 and a per-AP part 781-787. MAP PPDUs 775, in some cases, may beused for multiple purposes, which may include allowing a non-TxOP-owningAP (e.g., AP-2, AP-3, and AP-4) to respond to the TxOP owning AP (e.g.,AP-1) and provide information such as common information for one or moreSTAs of an AP. MAP PPDUs may also allow APs 105 to send coordinateddownlink multi-user data to associated STAs within resource units (RUs)789-795 within one or more sub-channels of the particular AP 105.

The common part 779 of preamble 777 may provide information thatindicates a mapping of AP identifier to an associated subchannel, andmay also indicate whether a per-AP part 781-787 is present or absent. Insome cases, the per-AP part 781-787 need not be present. The per-AP part781-785 of preamble 777, when present, may include information for STAsassociated with the AP. For example, the per-AP part 781-785 may includeone or more of a mapping of STA identifiers to particular RUs with inthe sub-channel of the AP. In some cases, the per-AP part 781-785 mayalso carry information meant for the TXOP-owner AP.

The STAs associated with each AP, in such cases, may decode thecommon-part 779 of the MAP-PPDU preamble 777 to determine itssub-channel, and tune to the sub-channel, then decode the correspondingper-AP part 781-787 of the preamble 777 that is sent within theallocated sub-channel, and determine a STA-ID to RU mapping or a mappingof broadcast RUs (or both). A receiving STA may then tune to the RU thatmaps to its STA-ID. If a STA is not included in a mapping of RUs, thatSTA may be allowed to go to doze state in some cases. In some examples,the indication of resource units for individual STAs or for a broadcastby an AP 105 may be in a signaling portion of the preamble 777, such asa new SIG-C portion that provides a RU mapping per STA-ID. Accordingly,the preamble 777 may indicate an allocation or assignment of resourceunits to each STA that will be receiving PSDU(s) from the AP during themulti-AP coordinated transmission, and in some cases, may indicateresource units associated with one or more PSDU(s) to be broadcast fromthe AP 105 to each STA associated with the AP 105 during the multi-APcoordinated transmission.

FIG. 8 illustrates an example of a protocol sequence for uplinkorthogonal frequency division multiple access (OFDMA) 800 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. In some examples,protocol sequence for uplink OFDMA 800 may implement aspects of wirelesscommunication system 100 or 200. In this example, first AP 105-a, secondAP 105-b, and third AP 105-c may perform coordinated transmissions inwhich concurrent scheduling of multiple APs 105 may be implemented.

Similarly as discussed above, in the example of FIG. 7, each of the APs105 may contend for access to a wireless channel during acontention/countdown window 805. In some cases, the first AP 105-a maybe the first to contend for channel access and may win the medium. Insome cases, similarly as discussed above, one or more of the other APs105 may attempt to access the channel before the first AP 105-a winscontention, but may not win contention. Upon winning thecontention-based channel access procedure, the first AP 105-a maytransmit a scheduling trigger such as a MAP-Sch-Trigger 810, which maybe received by the second AP 105-b and the third AP 105-b. TheMAP-Sch-Trigger 810 may be a MAP PPDU that the first AP 105-a transmitsto each neighboring AP 105 to initiate scheduling of multi-APcommunications. The second AP 105-b and the third AP 105-c, in thiscase, may perform multi-AP scheduling 815, such as according to any oneof the examples discussed herein. The first AP 105-a, based on themulti-AP scheduling 815 may, may determine resources for transmissionsof each AP 105, and may transmit a MAP-Trigger 820 to initiate themulti-AP coordinated transmissions.

In this example, multi-AP coordinated transmission may use OFDMA toprovide concurrent transmissions of multiple APs 105 and STAs, anduplink transmissions of the STAs may be triggered by a correspondingdownlink transmission from an AP. In this example, the first AP 105-amay transmit preamble 825 that spans a number of subchannels, andtrigger 830 using a first subchannel (e.g., a primary 20 MHz channel),while remaining subchannels are idle. The trigger 830 may trigger thecorresponding STA(s) to transmit a HE TB PPDU 835 in the firstsubchannel, while remaining subchannels are idle. The second AP 105-bmay transmit preamble 840 that spans a number of subchannels, andtrigger 845 using a second subchannel (e.g., a secondary 20 MHzchannel), while remaining subchannels are idle. The trigger 845 maytrigger the corresponding STA(s) to transmit a HE TB PPDU 850 in thesecond subchannel, while remaining subchannels are idle. The third AP105-c may transmit preamble 855 that spans a number of subchannels, andtrigger 860 using a third subchannel (e.g., a secondary 40 MHz channel),while remaining subchannels are idle. The trigger 860 may trigger thecorresponding STA(s) to transmit a HE TB PPDU 865 in all or a portion ofthe third subchannel, while remaining subchannels are idle. In someexamples, the HE TB PPDUs on different subchannels may end at differenttimes. In this example, the first AP 105-a, as the TXOP owner, mayindicate the sub-channel for each neighboring AP 105 in a similar manneras discussed above with respect to FIG. 7.

FIG. 9 shows a block diagram 900 of a device 905 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The device 905 may bean example of aspects of a AP as described herein. The device 905 mayinclude a receiver 910, a communications manager 915, and a transmitter920. The device 905 may also include a processor. Each of thesecomponents may be in communication with one another (e.g., via one ormore buses).

The receiver 910 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to multi-accesspoint scheduling in wireless local area networks, etc.). Information maybe passed on to other components of the device. The receiver 910 may bean example of aspects of the transceiver 1220 described with referenceto FIG. 12. The receiver 910 may utilize a single antenna or a set ofantennas.

The communications manager 915 may win a contention-based procedure fora transmission opportunity of a wireless channel, transmit to at least asecond AP, during a first portion of the transmission opportunity, afirst resource assignment for coordinated communications between thesecond AP and at least a first station during a second portion of thetransmission opportunity, transmit to at least the second AP anindication of a start of the second portion of the transmissionopportunity, and initiate, based on the indication, coordinatedcommunications between the first AP and at least a second stationassociated with the first AP during the second portion of thetransmission opportunity.

In some cases, the communications manager 915 may also receive, during afirst portion of a transmission opportunity reserved for communicationsby a first AP, a resource assignment from the first AP to schedulecoordinated communications over a second portion of the transmissionopportunity, transmit a scheduling indicator to at least one stationassociated with the second access point scheduling a subset of resourcesof the second portion of the transmission opportunity for thecoordinated communications indicated in the resource assignment, receivean indication of a start of the second portion of the transmissionopportunity, and initiate, based on the indication, coordinatedcommunications between the second AP and the at least one station duringthe second portion of the transmission opportunity.

In some cases, the communications manager 915 may also configure amulti-AP physical protocol data unit (MAP PPDU) transmission to schedulecoordinated communications with at least one station, transmit the MAPPPDU transmission upon reception of an indication of a start of a secondportion of a transmission opportunity, communicate with the stationbased on the MAP PPDU transmission, transmit to at least a second AP anindication of a start of a second portion of a transmission opportunityreserved for communications by the first AP, initiate, based on theindication, coordinated communications between the first AP and at leastone station associated with the first AP during the second portion ofthe transmission opportunity, receive an indication of a start of asecond portion of a transmission opportunity reserved for communicationsby a first AP, and initiate, based on the indication, coordinatedcommunications between the second AP and at least one station during thesecond portion of the transmission opportunity.

The communications manager 915 may be an example of aspects of thecommunications manager 1210 described herein. The communications manager1015, or its sub-components, may be implemented in hardware, code (e.g.,software or firmware) executed by a processor, or any combinationthereof. If implemented in code executed by a processor, the functionsof the communications manager 915, or its sub-components may be executedby a general-purpose processor, a DSP, an application-specificintegrated circuit (ASIC), a FPGA or other programmable logic device,discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described in thepresent disclosure.

The communications manager 915, or its sub-components, may be physicallylocated at various positions, including being distributed such thatportions of functions are implemented at different physical locations byone or more physical components. In some examples, the communicationsmanager 915, or its sub-components, may be a separate and distinctcomponent in accordance with various aspects of the present disclosure.In some examples, the communications manager 915, or its sub-components,may be combined with one or more other hardware components, includingbut not limited to an input/output (I/O) component, a transceiver, anetwork server, another computing device, one or more other componentsdescribed in the present disclosure, or a combination thereof inaccordance with various aspects of the present disclosure.

The transmitter 920 may transmit signals generated by other componentsof the device. In some examples, the transmitter 920 may be collocatedwith a receiver 910 in a transceiver module. For example, thetransmitter 920 may be an example of aspects of the transceiver 1220described with reference to FIG. 12. The transmitter 920 may utilize asingle antenna or a set of antennas.

In some examples, the communications manager 915 may be an example of awireless modem implemented as a separate chipset or as a component of asystem on chip (SoC), and the receiver 910 and transmitter 920 mayinclude analog components (e.g., amplifiers, filters, phase shifters,antennas, etc.) to facilitate the receipt and transmission of wirelesssignals. The communications manager 915 may obtain and decode signalsreceived wirelessly from the receiver 910 via a receive interface. Thecommunications manager 915 also may output signals for wirelesstransmission by the transmitter 920 over a transmit interface.

FIG. 10 shows a block diagram 1000 of a device 1005 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The device 1005 maybe an example of aspects of a device 905 or an AP 105 as describedherein. The device 1005 may include a receiver 1010, a communicationsmanager 1015, and a transmitter 1045. The device 1005 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

The receiver 1010 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to multi-accesspoint scheduling in wireless local area networks, etc.). Information maybe passed on to other components of the device. The receiver 1010 may bean example of aspects of the transceiver 1220 described with referenceto FIG. 12. The receiver 1010 may utilize a single antenna or a set ofantennas.

The communications manager 1015 may be an example of aspects of thecommunications manager 1015 as described herein. The communicationsmanager 1015 may include a channel contention manager 1020, a resourceassignment manager 1025, a multi-AP transmission manager 1030, acoordinated communications manager 1035, and a scheduling manager 1040.The communications manager 1015 may be an example of aspects of thecommunications manager 1210 described herein.

The channel contention manager 1020 may win a contention-based procedurefor a transmission opportunity of a wireless channel. As discussedherein, such a contention-based procedure may be, for example, an EDCAcontention procedure.

The resource assignment manager 1025 may transmit to at least a secondAP, during a first portion of the transmission opportunity, a firstresource assignment for coordinated communications between the second APand at least a first station during a second portion of the transmissionopportunity. In some cases, the resource assignment manager 1025 mayreceive, during the first portion of a transmission opportunity reservedfor communications by a first AP, a resource assignment from the firstAP to schedule coordinated communications over a second portion of thetransmission opportunity.

In some cases, the resource assignment manager 1025 may transmit to atleast a second AP an indication of a start of a second portion of atransmission opportunity reserved for communications by the first AP. Insome cases, the resource assignment manager 1025 may receive anindication of a start of a second portion of a transmission opportunityreserved for communications by a first AP.

The multi-AP transmission manager 1030 may transmit to at least thesecond AP an indication of a start of the second portion of thetransmission opportunity. In some cases, the multi-AP transmissionmanager 1030 may receive an indication of a start of the second portionof the transmission opportunity.

The coordinated communications manager 1035 may initiate, based on thereceived indication, coordinated communications between the first AP andat least a second station associated with the first AP during the secondportion of the transmission opportunity. In some cases, the coordinatedcommunications manager 1035 may initiate, based on the indication,coordinated communications between the second AP and the at least onestation during the second portion of the transmission opportunity. Insome cases, the coordinated communications manager 1035 may transmit theMAP PPDU transmission upon reception of an indication of a start of asecond portion of a transmission opportunity and communicate with thestation based on the MAP PPDU transmission.

The scheduling manager 1040 may transmit a scheduling indicator to atleast one station associated with the second access point scheduling asubset of resources of the second portion of the transmissionopportunity for the coordinated communications indicated in the resourceassignment. In some cases, the scheduling manager 1040 may configure aMAP PPDU transmission to schedule coordinated communications with atleast one station.

The transmitter 1045 may transmit signals generated by other componentsof the device. In some examples, the transmitter 1045 may be collocatedwith a receiver 1010 in a transceiver module. For example, thetransmitter 1045 may be an example of aspects of the transceiver 1220described with reference to FIG. 12. The transmitter 1045 may utilize asingle antenna or a set of antennas.

FIG. 11 shows a block diagram 1100 of a communications manager 1105 thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure. The communicationsmanager 1105 may be an example of aspects of a communications manager915, a communications manager 1015, or a communications manager 1210described herein. The communications manager 1105 may include a channelcontention manager 1110, a resource assignment manager 1115, a multi-APtransmission manager 1120, a coordinated communications manager 1125, aresource mapping component 1130, a scheduling manager 1135, and asubchannel resource manager 1140. Each of these modules may communicate,directly or indirectly, with one another (e.g., via one or more buses).

The channel contention manager 1110 may win a contention-based procedurefor a transmission opportunity of a wireless channel. As discussedherein, such a contention-based procedure may be, for example, an EDCAcontention procedure.

The resource assignment manager 1115 may transmit to at least a secondAP, during a first portion of the transmission opportunity, a firstresource assignment for coordinated communications between the second APand at least a first station during a second portion of the transmissionopportunity. In some examples, the resource assignment manager 1115 maytransmit to at least a second AP an indication of a start of a secondportion of a transmission opportunity reserved for communications by thefirst AP. In some examples, the resource assignment manager 1115 maytransmit to a third AP and based on the first scheduling indicator, asecond resource assignment for coordinated communications between thethird AP and at least a third station during the second portion of thetransmission opportunity.

In some examples, the resource assignment manager 1115 may configure theresource assignment in a single user physical protocol data unit (SUPPDU) format. In some examples, the resource assignment manager 1115 maytransmit the resource assignment allocating resources for coordinatedcommunications between the second AP at least a first station, andbetween a third AP and at least a third station. In some examples, theresource assignment manager 1115 may configure the resource assignmentto include an AP identifier and corresponding resources of the secondportion of the transmission opportunity for at least the second AP. Themulti-AP transmission manager 1120 may transmit to at least the secondAP an indication of a start of the second portion of the transmissionopportunity.

In some examples, the resource assignment manager 1115 may receive,during a first portion of a transmission opportunity reserved forcommunications by a first AP, a resource assignment from the first AP toschedule coordinated communications over a second portion of thetransmission opportunity. In some examples, the resource assignmentmanager 1115 may receive an indication of a start of a second portion ofa transmission opportunity reserved for communications by a first AP,and may receive an indication of a start of the second portion of thetransmission opportunity.

In some examples, the multi-AP transmission manager 1120 may receive afirst scheduling indicator from the second AP based on the firstresource assignment. In some examples, the multi-AP transmission manager1120 may receive a second scheduling indicator from the third AP basedon the second resource assignment.

The coordinated communications manager 1125 may initiate, based on theindication, coordinated communications between the first AP and at leasta second station associated with the first AP during the second portionof the transmission opportunity. In some examples, the coordinatedcommunications manager 1125 may initiate, based on the indication,coordinated communications between the second AP and the at least onestation during the second portion of the transmission opportunity. Insome examples, the coordinated communications manager 1125 may transmitthe MAP PPDU transmission upon reception of an indication of a start ofa second portion of a transmission opportunity. In some examples, thecoordinated communications manager 1125 may communicate with the stationbased on the MAP PPDU transmission.

In some examples, the coordinated communications manager 1125 mayconfigure the coordinated communications with at least the secondstation in a multi-AP physical protocol data unit (MAP PPDU) format orin a high efficiency trigger-based physical protocol data unit (HE TBPPDU) format. In some examples, the coordinated communications manager1125 may configure the coordinated communications with at least thesecond station to include an AP identifier for the second AP in astation identifier (STAID) field.

The resource mapping component 1130 may configure the coordinatedcommunications with at least the second station to include a mapping ofan AP identifier for the second AP to corresponding resources of thesecond portion of the transmission opportunity for at least the secondAP, where the mapping is configured to be located in a new field of ahigh efficiency trigger-based physical protocol data unit (HE TB PPDU).

The scheduling manager 1135 may transmit a scheduling indicator to atleast one station associated with the second access point scheduling asubset of resources of the second portion of the transmissionopportunity for the coordinated communications indicated in the resourceassignment. In some examples, the scheduling manager 1135 may configurea multi-AP physical protocol data unit (MAP PPDU) transmission toschedule coordinated communications with at least one station. In someexamples, the scheduling manager 1135 may configure the schedulingindicator in a single user physical protocol data unit (SU PPDU) format.In some examples, the scheduling manager 1135 may configure thescheduling indicator in a multi-AP physical protocol data unit (MAPPPDU) format. In some examples, the scheduling manager 1135 mayconfigure the scheduling indicator to include, in a scheduling indicatorpreamble, an AP identifier for the second AP and a correspondingsubchannel indication for the at least one station to monitor for ascheduling indicator payload.

In some examples, the scheduling manager 1135 may configure thescheduling indicator to include an AP identifier for the second AP in astation identifier (STAID) field. The subchannel resource manager 1140may receive, in the resource assignment, information indicative of thecorresponding subchannel for the second AP. In some examples, thesubchannel resource manager 1140 may transmit the scheduling indicatorpayload over the corresponding subchannel based on the resourceassignment.

In some examples, the subchannel resource manager 1140 may transmit thescheduling indicator preamble over a channel simultaneously with atleast a third AP, where the scheduling indicator further includes an APidentifier for the third AP and a corresponding subchannel indicationfor the at least a second station associated with the third AP tomonitor for a scheduling indicator payload. In some cases, the channelincludes a primary channel for the first AP.

FIG. 12 shows a diagram of a system 1200 including a device 1205 thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure. The device 1205may be an example of or include the components of device 905, device1005, device 3705, device 3805, device 4005, or an AP as describedherein. The device 1205 may include components for bi-directional voiceand data communications including components for transmitting andreceiving communications, including a communications manager 1210, anetwork communications manager 1215, a transceiver 1220, an antenna1225, memory 1230, a processor 1240, and an inter-station communicationsmanager 1245. These components may be in electronic communication viaone or more buses (e.g., bus 1250).

The communications manager 1210 may be an example of the communicationsmanager 915 or the communications manager 1005, or the communicationsmanager 3705, or the communications manager 3815, or the communicationsmanager 3905, or the communications manager 4010 described herein. Thecommunications manager 1210 may win a contention-based procedure for atransmission opportunity of a wireless channel, transmit to at least asecond AP, during a first portion of the transmission opportunity, afirst resource assignment for coordinated communications between thesecond AP and at least a first station during a second portion of thetransmission opportunity, transmit to at least the second AP anindication of a start of the second portion of the transmissionopportunity, and initiate, based on the indication, coordinatedcommunications between the first AP and at least a second stationassociated with the first AP during the second portion of thetransmission opportunity.

In some cases, the communications manager 1210 may also receive, duringa first portion of a transmission opportunity reserved forcommunications by a first AP, a resource assignment from the first AP toschedule coordinated communications over a second portion of thetransmission opportunity, transmit a scheduling indicator to at leastone station associated with the second access point scheduling a subsetof resources of the second portion of the transmission opportunity forthe coordinated communications indicated in the resource assignment,receive an indication of a start of the second portion of thetransmission opportunity, and initiate, based on the indication,coordinated communications between the second AP and the at least onestation during the second portion of the transmission opportunity.

In some cases, the communications manager 1210 may also configure amulti-AP physical protocol data unit (MAP PPDU) transmission to schedulecoordinated communications with at least one station, transmit the MAPPPDU transmission upon reception of an indication of a start of a secondportion of a transmission opportunity, communicate with the stationbased on the MAP PPDU transmission, transmit to at least a second AP anindication of a start of a second portion of a transmission opportunityreserved for communications by the first AP, initiate, based on theindication, coordinated communications between the first AP and at leastone station associated with the first AP during the second portion ofthe transmission opportunity, receive an indication of a start of asecond portion of a transmission opportunity reserved for communicationsby a first AP, and initiate, based on the indication, coordinatedcommunications between the second AP and at least one station during thesecond portion of the transmission opportunity.

The network communications manager 1215 may manage communications with anetwork (e.g., via one or more wired backhaul links). For example, thenetwork communications manager 1215 may manage the transfer of datacommunications for client devices, such as one or more STAs 115.

The transceiver 1220 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1220 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1220 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1225.However, in some cases the device may have more than one antenna 1225,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 1230 may include RAM and ROM. The memory 1230 may storecomputer-readable, computer-executable code 1235 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 1230 may contain, amongother things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

The processor 1240 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 1240 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 1240. The processor 1240 may be configuredto execute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting multi-accesspoint scheduling in wireless local area networks).

FIG. 13 shows a block diagram 1300 of a device 1305 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The device 1305 maybe an example of aspects of a STA as described herein. The device 1305may include a receiver 1310, a communications manager 1315, and atransmitter 1320. The device 1305 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

Receiver 1310 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to multi-accesspoint scheduling in wireless local area networks, etc.). Information maybe passed on to other components of the device. The receiver 1310 may bean example of aspects of the transceiver 1620 described with referenceto FIG. 16. The receiver 1310 may utilize a single antenna or a set ofantennas.

The communications manager 1315 may receive, during a first portion of atransmission opportunity and from an AP, a scheduling indicatorconfigured to schedule a set of resources of a transmission opportunityfor coordinated communications, the transmission opportunity reservedfor communications by a first AP and initiate coordinated communicationswith the second AP and over the subset of resources of the transmissionopportunity based on the scheduling indicator.

In some cases, the communications manager 1315 may also receive amulti-AP physical protocol data unit (MAP PPDU) transmission to schedulecoordinated communications with a AP and communicate with the AP basedon the MAP PPDU transmission. The communications manager 1315 may be anexample of aspects of the communications manager 1610 described herein.

The communications manager 1215, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 1215, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 1215, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 1215, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 1215, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

Transmitter 1220 may transmit signals generated by other components ofthe device. In some examples, the transmitter 1220 may be collocatedwith a receiver 1210 in a transceiver module. For example, thetransmitter 1220 may be an example of aspects of the transceiver 1620described with reference to FIG. 16. The transmitter 1220 may utilize asingle antenna or a set of antennas.

In some examples, the communications manager 1315 may be an example of awireless modem implemented as a separate chipset or as a component of asystem on chip (SoC), and the receiver 1310 and transmitter 1320 mayinclude analog components (e.g., amplifiers, filters, phase shifters,antennas, etc.) to facilitate the receipt and transmission of wirelesssignals. The communications manager 1315 may obtain and decode signalsreceived wirelessly from the receiver 1310 via a receive interface. Thecommunications manager 1315 also may output signals for wirelesstransmission by the transmitter 1320 over a transmit interface.

FIG. 14 shows a block diagram 1400 of a device 1405 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The device 1405 maybe an example of aspects of a device 1405 or a STA 115 as describedherein. The device 1405 may include a receiver 1410, a communicationsmanager 1415, and a transmitter 1430. The device 1405 may also include aprocessor. Each of these components may be in communication with oneanother (e.g., via one or more buses).

Receiver 1410 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to multi-accesspoint scheduling in wireless local area networks, etc.). Information maybe passed on to other components of the device. The receiver 1410 may bean example of aspects of the transceiver 1620 described with referenceto FIG. 16. The receiver 1410 may utilize a single antenna or a set ofantennas.

The communications manager 1415 may be an example of aspects of thecommunications manager 1315 as described herein. The communicationsmanager 1415 may include a scheduling manager 1420 and a coordinatedcommunications manager 1425. The communications manager 1415 may be anexample of aspects of the communications manager 1710 described herein.

The scheduling manager 1420 may receive, during a first portion of atransmission opportunity and from an AP, a scheduling indicatorconfigured to schedule a set of resources of a transmission opportunityfor coordinated communications, the transmission opportunity reservedfor communications by a first AP. In some examples, the schedulingmanager 1420 may receive a multi-AP physical protocol data unit (MAPPPDU) transmission to schedule coordinated communications with a AP.

The coordinated communications manager 1425 may initiate coordinatedcommunications with the second AP and over the subset of resources ofthe transmission opportunity based on the scheduling indicator. Forexample, the coordinated communications manager 1425 may communicatewith the AP based on the MAP PPDU transmission.

Transmitter 1430 may transmit signals generated by other components ofthe device. In some examples, the transmitter 1430 may be collocatedwith a receiver 1410 in a transceiver module. For example, thetransmitter 1430 may be an example of aspects of the transceiver 1620described with reference to FIG. 16. The transmitter 1430 may utilize asingle antenna or a set of antennas.

FIG. 15 shows a block diagram 1500 of a communications manager 1505 thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure. The communicationsmanager 1505 may be an example of aspects of a communications manager1415, a communications manager 1515, or a communications manager 1710described herein. The communications manager 1505 may include ascheduling manager 1510, a coordinated communications manager 1515, asubchannel resource manager 1520, and a resource mapping component 1525.Each of these modules may communicate, directly or indirectly, with oneanother (e.g., via one or more buses).

The scheduling manager 1510 may receive, during a first portion of atransmission opportunity and from an AP, a scheduling indicatorconfigured to schedule a set of resources of a transmission opportunityfor coordinated communications, the transmission opportunity reservedfor communications by a first AP. In some examples, the schedulingmanager 1510 may receive a multi-AP physical protocol data unit (MAPPPDU) transmission to schedule coordinated communications with a AP. Insome examples, the scheduling manager 1510 may receive the schedulingindicator in a single user physical protocol data unit (SU PPDU) format.In some cases, the scheduling indicator includes an AP identifier forthe second AP in a station identifier (STAID) field.

The coordinated communications manager 1515 may initiate coordinatedcommunications with the second AP and over the subset of resources ofthe transmission opportunity based on the scheduling indicator. In someexamples, the coordinated communications manager 1515 may communicatewith the AP based on the MAP PPDU transmission.

In some examples, the coordinated communications manager 1515 mayreceive the coordinated communications with the second AP in a multi-APphysical protocol data unit (MAP PPDU) format or in a high efficiencytrigger-based physical protocol data unit (HE TB PPDU) format.

The subchannel resource manager 1520 may receive, in a schedulingindicator preamble, an AP identifier for the second AP and acorresponding subchannel indication. In some examples, the subchannelresource manager 1520 may monitor the corresponding subchannel for ascheduling indicator payload based on the scheduling indicator preamble.In some cases, the scheduling indicator further includes an APidentifier for the third AP and a corresponding subchannel indicationfor the at least a second station associated with the third AP tomonitor for a scheduling indicator payload. In some cases, the channelincludes a primary channel for the first AP.

The resource mapping component 1525 may map resources with differentAPs. In some cases, the coordinated communications with the second APincludes a mapping of an AP identifier for the second AP tocorresponding resources of the second portion of the transmissionopportunity for at least the second AP, where the mapping is configuredto be located in a new field of a high efficiency trigger-based physicalprotocol data unit (HE TB PPDU).

FIG. 16 shows a diagram of a system 1600 including a device 1605 thatsupports multi-access point scheduling in wireless local area networksin accordance with aspects of the present disclosure. The device 1605may be an example of or include the components of device 1405, device1505, or a STA as described herein. The device 1605 may includecomponents for bi-directional voice and data communications includingcomponents for transmitting and receiving communications, including acommunications manager 1610, an I/O controller 1615, a transceiver 1620,an antenna 1625, memory 1630, and a processor 1640. These components maybe in electronic communication via one or more buses (e.g., bus 1645).

The communications manager 1610 may receive, during a first portion of atransmission opportunity and from an AP, a scheduling indicatorconfigured to schedule a set of resources of a transmission opportunityfor coordinated communications, the transmission opportunity reservedfor communications by a first AP and initiate coordinated communicationswith the second AP and over the subset of resources of the transmissionopportunity based on the scheduling indicator.

In some cases, the communications manager 1610 may also receive amulti-AP physical protocol data unit (MAP PPDU) transmission to schedulecoordinated communications with a AP and communicate with the AP basedon the MAP PPDU transmission.

I/O controller 1615 may manage input and output signals for device 1605.I/O controller 1615 may also manage peripherals not integrated intodevice 1605. In some cases, I/O controller 1615 may represent a physicalconnection or port to an external peripheral. In some cases, I/Ocontroller 1615 may utilize an operating system such as iOS®, ANDROID®,MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operatingsystem. In other cases, I/O controller 1615 may represent or interactwith a modem, a keyboard, a mouse, a touchscreen, or a similar device.In some cases, I/O controller 1615 may be implemented as part of aprocessor. In some cases, a user may interact with device 1605 via I/Ocontroller 1615 or via hardware components controlled by I/O controller1615.

Transceiver 1620 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 1620 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 1620 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1625.However, in some cases the device may have more than one antenna 1625,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

Memory 1630 may include RAM and ROM. The memory 1630 may storecomputer-readable, computer-executable software 1635 includinginstructions that, when executed, cause the processor to perform variousfunctions described herein. In some cases, the memory 1630 may contain,among other things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

Processor 1640 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, processor 1640 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 1640. Processor 1640 may be configured toexecute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting multi-accesspoint scheduling in wireless local area networks).

FIG. 17 shows a flowchart illustrating a method 1700 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 1700 may be implemented by a AP or its components as describedherein. For example, the operations of method 1700 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 1705, the AP may win a contention-based procedure for a transmissionopportunity of a wireless channel. The operations of 1705 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1705 may be performed by a channelcontention manager as described with reference to FIGS. 9 through 12.

At 1710, the AP may transmit to at least a second AP, during a firstportion of the transmission opportunity, a first resource assignment forcoordinated communications between the second AP and at least a firststation during a second portion of the transmission opportunity. Theoperations of 1710 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1710 may beperformed by a resource assignment manager as described with referenceto FIGS. 9 through 12.

At 1715, the AP may transmit to at least the second AP an indication ofa start of the second portion of the transmission opportunity. Theoperations of 1715 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1715 may beperformed by a multi-AP transmission manager as described with referenceto FIGS. 9 through 12.

At 1720, the AP may initiate, based on the indication, coordinatedcommunications between the first AP and at least a second stationassociated with the first AP during the second portion of thetransmission opportunity. The operations of 1720 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1720 may be performed by a coordinated communicationsmanager as described with reference to FIGS. 9 through 12.

FIG. 18 shows a flowchart illustrating a method 1800 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 1800 may be implemented by a AP or its components as describedherein. For example, the operations of method 1800 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 1805, the AP may win a contention-based procedure for a transmissionopportunity of a wireless channel. The operations of 1805 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1805 may be performed by a channelcontention manager as described with reference to FIGS. 9 through 12.

At 1810, the AP may transmit to at least a second AP, during a firstportion of the transmission opportunity, a first resource assignment forcoordinated communications between the second AP and at least a firststation during a second portion of the transmission opportunity. Theoperations of 1810 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1810 may beperformed by a resource assignment manager as described with referenceto FIGS. 9 through 12.

At 1815, the AP may transmit to at least the second AP an indication ofa start of the second portion of the transmission opportunity. Theoperations of 1815 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1815 may beperformed by a multi-AP transmission manager as described with referenceto FIGS. 9 through 12.

At 1820, the AP may initiate, based on the indication, coordinatedcommunications between the first AP and at least a second stationassociated with the first AP during the second portion of thetransmission opportunity. The operations of 1820 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 1820 may be performed by a coordinated communicationsmanager as described with reference to FIGS. 9 through 12.

At 1825, the AP may receive a first scheduling indicator from the secondAP based on the first resource assignment. The operations of 1825 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1825 may be performed by a multi-APtransmission manager as described with reference to FIGS. 9 through 12.

At 1830, the AP may transmit to a third AP and based on the firstscheduling indicator, a second resource assignment for coordinatedcommunications between the third AP and at least a third station duringthe second portion of the transmission opportunity. The operations of1830 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1830 may be performed by aresource assignment manager as described with reference to FIGS. 9through 12.

At 1835, the AP may receive a second scheduling indicator from the thirdAP based on the second resource assignment. The operations of 1835 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 1835 may be performed by amulti-AP transmission manager as described with reference to FIGS. 9through 12.

FIG. 19 shows a flowchart illustrating a method 1900 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 1900 may be implemented by a AP or its components as describedherein. For example, the operations of method 1900 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 1905, the AP may receive, during a first portion of a transmissionopportunity reserved for communications by a first AP, a resourceassignment from the first AP to schedule coordinated communications overa second portion of the transmission opportunity. The operations of 1905may be performed according to the methods described herein. In someexamples, aspects of the operations of 1905 may be performed by aresource assignment manager as described with reference to FIGS. 9through 12.

At 1910, the AP may transmit a scheduling indicator to at least onestation associated with the second access point scheduling a subset ofresources of the second portion of the transmission opportunity for thecoordinated communications indicated in the resource assignment. Theoperations of 1910 may be performed according to the methods describedherein. In some examples, aspects of the operations of 1910 may beperformed by a scheduling manager as described with reference to FIGS. 9through 12.

At 1915, the AP may receive an indication of a start of the secondportion of the transmission opportunity. The operations of 1915 may beperformed according to the methods described herein. In some examples,aspects of the operations of 1915 may be performed by a multi-APtransmission manager as described with reference to FIGS. 9 through 12.

At 1920, the AP may initiate, based on the indication, coordinatedcommunications between the second AP and the at least one station duringthe second portion of the transmission opportunity. The operations of1920 may be performed according to the methods described herein. In someexamples, aspects of the operations of 1920 may be performed by acoordinated communications manager as described with reference to FIGS.9 through 12.

FIG. 20 shows a flowchart illustrating a method 2000 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2000 may be implemented by a AP or its components as describedherein. For example, the operations of method 2000 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 2005, the AP may receive, during a first portion of a transmissionopportunity reserved for communications by a first AP, a resourceassignment from the first AP to schedule coordinated communications overa second portion of the transmission opportunity. The operations of 2005may be performed according to the methods described herein. In someexamples, aspects of the operations of 2005 may be performed by aresource assignment manager as described with reference to FIGS. 9through 12.

At 2010, the AP may transmit a scheduling indicator to at least onestation associated with the second access point scheduling a subset ofresources of the second portion of the transmission opportunity for thecoordinated communications indicated in the resource assignment. Theoperations of 2010 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2010 may beperformed by a scheduling manager as described with reference to FIGS. 9through 12.

At 2015, the AP may receive an indication of a start of the secondportion of the transmission opportunity. The operations of 2015 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2015 may be performed by a multi-APtransmission manager as described with reference to FIGS. 9 through 12.

At 2020, the AP may initiate, based on the indication, coordinatedcommunications between the second AP and the at least one station duringthe second portion of the transmission opportunity. The operations of2020 may be performed according to the methods described herein. In someexamples, aspects of the operations of 2020 may be performed by acoordinated communications manager as described with reference to FIGS.9 through 12.

At 2025, the AP may configure the scheduling indicator in a multi-APphysical protocol data unit (MAP PPDU) format. The operations of 2025may be performed according to the methods described herein. In someexamples, aspects of the operations of 2025 may be performed by ascheduling manager as described with reference to FIGS. 9 through 12.

At 2030, the AP may configure the scheduling indicator to include, in ascheduling indicator preamble, an AP identifier for the second AP and acorresponding subchannel indication for the at least one station tomonitor for a scheduling indicator payload. The operations of 2030 maybe performed according to the methods described herein. In someexamples, aspects of the operations of 2030 may be performed by ascheduling manager as described with reference to FIGS. 9 through 12.

At 2035, the AP may receive, in the resource assignment, informationindicative of the corresponding subchannel for the second AP. Theoperations of 2035 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2035 may beperformed by a subchannel resource manager as described with referenceto FIGS. 9 through 12.

At 2040, the AP may transmit the scheduling indicator payload over thecorresponding subchannel based on the resource assignment. Theoperations of 2040 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2040 may beperformed by a subchannel resource manager as described with referenceto FIGS. 9 through 12.

At 2045, the AP may transmit the scheduling indicator preamble over achannel simultaneously with at least a third AP, where the schedulingindicator further includes an AP identifier for the third AP and acorresponding subchannel indication for the at least a second stationassociated with the third AP to monitor for a scheduling indicatorpayload. The operations of 2045 may be performed according to themethods described herein. In some examples, aspects of the operations of2045 may be performed by a subchannel resource manager as described withreference to FIGS. 9 through 12.

FIG. 21 shows a flowchart illustrating a method 2100 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2100 may be implemented by a STA or its components as describedherein. For example, the operations of method 2100 may be performed by acommunications manager as described with reference to FIGS. 13 through16. In some examples, a STA may execute a set of instructions to controlthe functional elements of the STA to perform the functions describedbelow. Additionally or alternatively, a STA may perform aspects of thefunctions described below using special-purpose hardware.

At 2105, the STA may receive, during a first portion of a transmissionopportunity and from an AP, a scheduling indicator configured toschedule a set of resources of a transmission opportunity forcoordinated communications, the transmission opportunity reserved forcommunications by a first AP. The operations of 2105 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2105 may be performed by a scheduling manager asdescribed with reference to FIGS. 13 through 16.

At 2110, the STA may initiate coordinated communications with the secondAP and over the subset of resources of the transmission opportunitybased on the scheduling indicator. The operations of 2110 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2110 may be performed by a coordinatedcommunications manager as described with reference to FIGS. 13 through16.

FIG. 22 shows a flowchart illustrating a method 2200 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2200 may be implemented by a STA or its components as describedherein. For example, the operations of method 2200 may be performed by acommunications manager as described with reference to FIGS. 13 through16. In some examples, a STA may execute a set of instructions to controlthe functional elements of the STA to perform the functions describedbelow. Additionally or alternatively, a STA may perform aspects of thefunctions described below using special-purpose hardware.

At 2205, the STA may receive, during a first portion of a transmissionopportunity and from an AP, a scheduling indicator configured toschedule a set of resources of a transmission opportunity forcoordinated communications, the transmission opportunity reserved forcommunications by a first AP. The operations of 2205 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2205 may be performed by a scheduling manager asdescribed with reference to FIGS. 13 through 16.

At 2210, the STA may receive, in a scheduling indicator preamble, an APidentifier for the second AP and a corresponding subchannel indication.The operations of 2210 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 2210may be performed by a subchannel resource manager as described withreference to FIGS. 13 through 16.

At 2215, the STA may monitor the corresponding subchannel for ascheduling indicator payload based on the scheduling indicator preamble.The operations of 2215 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 2215may be performed by a subchannel resource manager as described withreference to FIGS. 13 through 16.

At 2220, the STA may initiate coordinated communications with the secondAP and over the subset of resources of the transmission opportunitybased on the scheduling indicator. The operations of 2220 may beperformed according to the methods described herein. In some examples,aspects of the operations of 2220 may be performed by a coordinatedcommunications manager as described with reference to FIGS. 13 through16.

FIG. 23 shows a flowchart illustrating a method 2300 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2300 may be implemented by a AP or its components as describedherein. For example, the operations of method 2300 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 2305, the AP may configure a multi-AP physical protocol data unit(MAP PPDU) transmission to schedule coordinated communications with atleast one station. The operations of 2305 may be performed according tothe methods described herein. In some examples, aspects of theoperations of 2305 may be performed by a scheduling manager as describedwith reference to FIGS. 9 through 12.

At 2310, the AP may transmit the MAP PPDU transmission upon reception ofan indication of a start of a second portion of a transmissionopportunity. The operations of 2310 may be performed according to themethods described herein. In some examples, aspects of the operations of2310 may be performed by a coordinated communications manager asdescribed with reference to FIGS. 9 through 12.

At 2315, the AP may communicate with the station based on the MAP PPDUtransmission. The operations of 2315 may be performed according to themethods described herein. In some examples, aspects of the operations of2315 may be performed by a coordinated communications manager asdescribed with reference to FIGS. 9 through 12.

FIG. 24 shows a flowchart illustrating a method 2400 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2400 may be implemented by a STA or its components as describedherein. For example, the operations of method 2400 may be performed by acommunications manager as described with reference to FIGS. 13 through16. In some examples, a STA may execute a set of instructions to controlthe functional elements of the STA to perform the functions describedbelow. Additionally or alternatively, a STA may perform aspects of thefunctions described below using special-purpose hardware.

At 2405, the STA may receive a multi-AP physical protocol data unit (MAPPPDU) transmission to schedule coordinated communications with a AP. Theoperations of 2405 may be performed according to the methods describedherein. In some examples, aspects of the operations of 2405 may beperformed by a scheduling manager as described with reference to FIGS.13 through 16.

At 2410, the STA may communicate with the AP based on the MAP PPDUtransmission. The operations of 2410 may be performed according to themethods described herein. In some examples, aspects of the operations of2410 may be performed by a coordinated communications manager asdescribed with reference to FIGS. 13 through 16.

FIG. 25 shows a flowchart illustrating a method 2500 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2500 may be implemented by a AP or its components as describedherein. For example, the operations of method 2500 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 2505, the AP may transmit to at least a second AP an indication of astart of a second portion of a transmission opportunity reserved forcommunications by the first AP. The operations of 2505 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 2505 may be performed by a resource assignment manageras described with reference to FIGS. 9 through 12.

At 2510, the AP may initiate, based on the indication, coordinatedcommunications between the first AP and at least one station associatedwith the first AP during the second portion of the transmissionopportunity. The operations of 2510 may be performed according to themethods described herein. In some examples, aspects of the operations of2510 may be performed by a coordinated communications manager asdescribed with reference to FIGS. 9 through 12.

FIG. 26 shows a flowchart illustrating a method 2600 that supportsmulti-access point scheduling in wireless local area networks inaccordance with aspects of the present disclosure. The operations ofmethod 2600 may be implemented by a AP or its components as describedherein. For example, the operations of method 2600 may be performed by acommunications manager as described with reference to FIGS. 9 through12. In some examples, a AP may execute a set of instructions to controlthe functional elements of the AP to perform the functions describedbelow. Additionally or alternatively, a AP may perform aspects of thefunctions described below using special-purpose hardware.

At 2605, the AP may receive an indication of a start of a second portionof a transmission opportunity reserved for communications by a first AP.The operations of 2605 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 2605may be performed by a resource assignment manager as described withreference to FIGS. 9 through 12.

At 2610, the AP may initiate, based on the indication, coordinatedcommunications between the second AP and at least one station during thesecond portion of the transmission opportunity. The operations of 2610may be performed according to the methods described herein. In someexamples, aspects of the operations of 2610 may be performed by acoordinated communications manager as described with reference to FIGS.9 through 12.

FIG. 27 illustrates an example of a MU transmission scheme 2700 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 2700 may implement aspects of WLAN 100. One or moreaspects of the MU transmission scheme 2700 may be implemented by awireless station and/or an AP, which may be examples of thecorresponding devices described herein.

Aspects of the MU transmission scheme 2700 may be implemented in awireless network, such as a Wi-Fi network implementing the one or more802.11 family of standards, e.g., 802.11ax, 802.11ac, or some otherWi-Fi standard. Aspects of the MU transmission scheme 2700 may beimplement by a set of AP(s) participating in a MU transmission. TheAP(s) may belong to the same BSS and/or may belong to different BSSs. Insome aspects, the AP that is coordinating the MU transmission may beconsidered a master AP (or first AP) and other AP(s) participating inthe MU transmission may be considered slave AP(s) (or second AP(s) orneighboring AP(s)).

In some aspects, wireless networks may be configured to support MUtransmissions. Broadly, the MU transmissions may include uplink and/ordownlink transmissions between AP(s) and their associated wirelessstations. Conventionally, the master AP obtains access to the channelfor a TxOP in which there are unused or available resources. In responseto the master AP determining that resources are available, the master APautonomously allocates resources to neighboring AP(s) and transmits theresource allocation in the first frame of the TxOP. The neighboringAP(s) receive the resource allocation in the first frame and use theallocated resources to participate in the MU transmission to the extentthat they are able with the allocated resources. However, conventionaltechniques do not provide a mechanism that allows the master AP todynamically allocate resources to the neighboring AP(s). Instead, themaster AP uses other processes/information to decide which resources areallocated to which neighboring AP. This conventional approach isunreliable as the information relied on by the master AP may be stale,e.g., may be based on outdated information that does not currentlyreflect the resource needs of the neighboring AP(s). However, MUtransmission scheme 2700 illustrates an example method to address this,and other, shortcomings of such conventional techniques.

Broadly, the MU transmission scheme 2700 may be divided into a resourceoffer and request phase (e.g., a first portion of the TxOP) and atriggered transmission phase (e.g., a second portion of the TxOP). Theresource offer and request phase may generally include a first stage2705 (e.g., stage 1) and a second stage 2710 (e.g., stage 2) and thetriggered transmission phase may include a third stage (e.g., stage 3)and a fourth stage 2725 (e.g., stage 4), with an optional stage 2720(e.g., stage 3a).

Broadly, stage 1 may include a first AP (e.g., a master AP) transmittingor otherwise providing an indication of an request or invitation toparticipate in a MU transmission to one or more second AP(s) (e.g., oneor more slave or neighboring AP(s)). In some aspects, stage 1 mayinclude the first AP transmitting, to a second AP and during the firstportion of the TxOP, a request to participate in a MU transmissionduring a second portion of the TxOP. That is, the stages of the resourceoffer and request phase may include the master AP preparing to transmiton a channel during a TxOP and realizing that there is a lack ofefficient usage of frequency/time/spatial resources during the TxOP. Toimprove resource utilization, the master AP may send out an invitationto neighboring AP(s) (AP(s) associated with the same BSS as the masterAP and/or associated with different BSSs) to participate in the MUtransmission.

In some aspects, stage 1 may include the master AP offeringtime/frequency/spatial resources in the upcoming coordinated the MUtransmission to neighboring AP(s). This may be a broadcast message tothe neighboring AP(s) that may indicate information such as the TxOPduration, an amount of available bandwidth, a number of availablespatial dimensions, and the like. In some aspects, this may include themaster AP indicating how the neighboring AP(s) should transmit duringstage 2. For example, the request or invitation to participate may carryor otherwise convey an indication of the channel on which theneighboring AP is to transmit its stage 2 transmission and/or thetransmission schedule (e.g., such as MU-MIMO, OFDMA, scheduled, polled,and the like). In some aspects, the request or invitation to participatemay carry or convey an indication of whether the neighboring AP(s)should transmit to their respective wireless station(s) after completionof their intent to participate message (e.g., the stage 2 transmission).This may support power control functions. In some aspects, the requestor invitation to participate may carry or convey an indication of amaximum amount of interference the master AP can tolerate, which may beusable by the neighboring AP(s) in setting their respective powercontrol levels. In some aspects, the neighboring AP(s) may use thetransmission of the request or invitation to participate toperform/update their time and/or carrier frequency synchronization withthe master AP.

In some aspects, the request or invitation to participate may carry orotherwise convey a variety of information usable by the neighboringAP(s) for a variety of purposes. Examples include, but are not limitedto the duration of the TxOP, one or more timing parameters of the TxOP(e.g., start time, an end time, etc.), the available bandwidth for theMU transmission, one or more spatial dimension(s) for the MUtransmission, a configuration for the neighboring AP(s) to use totransmit the indication of the intent to participate (e.g., one or moreresources), a scheduling for the neighboring AP(s) to transmit theindication of intent to participate, a transmission direction for the MUtransmission (e.g., uplink and/or downlink indication), and an availableinterference level for the master AP, an identifier for one or more ofthe neighboring AP(s), an identifier associated with a group ofneighboring AP(s) participating in the MU transmission, a transmit powerof the master AP, and the like. Other configurations details may also beincluded or otherwise conveyed in the request or invitation toparticipate message.

Broadly, stage 2 may include one or more neighboring AP(s) (e.g., slaveAP(s) or second AP(s)) responding to the request or invitation toparticipate with an indication of an intent to participate thatadditionally carries or otherwise conveys an indication of a resourcerequest for the corresponding neighbor AP. That is, stage 2 may includethe neighboring AP(s) that wish to participate in the MU transmissionresponding with an intent to participate message or signal to the masterAP. The neighboring AP(s) that wish to participate may respond bytransmitting or otherwise providing the indication of the intent toparticipate that requests resources for the MU transmission, with themaster AP allocating resources to the neighboring AP(s) based on theirrespective needs. In some aspects, the intent to participate may bereceived from neighboring AP(s) in parallel (e.g., all of the sametime), according to a transmission schedule, and/or based on a pollingsignal transmitted by the master AP. In some aspects, one or more of theneighboring AP(s) may configure the indication of intent to participateto additionally indicate a channel power management request for theirrespective wireless station(s) to measure the channel power using thetrigger signal of stage 3.

In some aspects, the neighboring AP(s) may transmit the intent toparticipate to the master AP and to any wireless station(s) associatedwith the neighboring AP. In some aspects, the intent to participate maybe transmitted in a single protocol data unit that may identify thewireless station(s), whether a channel power management request is to beperformed by the wireless station(s), and the like. In other aspects,the neighboring AP(s) may break up the transmission into two protocoldata units. For example, in a first protocol data unit the neighboringAP may transmit the intent to participate to the master AP. In a secondprotocol data unit, the neighboring AP may transmit the intent toparticipate to each of the wireless station(s) that are associated withthe neighboring AP and that are participating in the MU transmission. Inthis example, the second protocol data unit may carry or otherwiseprovide an indication of the identifier for the wireless station(s)and/or a channel power measurement request for the wireless station(s)to measure channel power (e.g., receive power level) using the triggersignal of stage 3.

In some aspects, stage 2 may include each neighboring AP transmitting orotherwise providing a message to the master AP that indicates whetherthey plan to participate in the MU transmission and, if so, the quantityof resources they are requesting. In some aspects, the neighboring AP(s)may transmit to the wireless station(s) to indicate to them that theyshould measure the receive power level of the next transmission (e.g.,the stage 3 trigger signal transmitted by the master AP). In someexamples, the master AP may configure the request or invitation toparticipate message to indicate whether the neighboring AP(s) are totransmit this information to their respective wireless station(s). Insome aspects, the wireless station(s) associated with the neighboring APmay measure the received power (e.g., RSSI) from the master AP to setthe power control in stage 4, e.g., in the case of an uplink coordinatedMU transmission.

In some aspects, stage 3 of the triggered transmission phase may includethe master AP transmitting or otherwise providing an indication of atrigger signal to the participating neighboring AP(s) (e.g., the slaveor second AP(s)). In some aspects, the trigger signal may carry orotherwise provide an indication of resources for each of theparticipating neighboring AP(s) to use during the MU transmission. Forexample, the master AP may determine the resource need for eachneighboring AP based on the intent to participate message and allocatethe unused resources within the TxOP based on the needs of theneighboring AP(s). The trigger signal may be configured to provide anindication (explicitly and/or implicitly) to each respective neighboringAP of which resources are allocated to it. In some aspects, the triggersignal may provide an indication of timing for the neighboring AP(s) touse during the MU transmission. In some aspects, the master AP mayadditionally configure the trigger signal to carry or otherwise conveyan indication of a guard interval duration for the MU transmission, apreamble configuration for the MU transmission, a transmission directionfor the MU transmission, an allowable interference level for the masterAP, an indication of whether the optional channel sounding stage (e.g.,stage 3a) it is to be performed, and the like.

In some aspects, stage 3 may include the master AP assigning channels tothe neighboring AP(s). In the example where two neighboring AP(s) areassigned the same channel at the same time, they may perform acoordinated beamforming to avoid interference, collision, and the like.In some aspects, the master AP may indicate or otherwise specify thestructure of the MU transmission in stage 4, e.g., to ensureorthogonality. In some aspects, this may include the master APindicating the time for the start of the stage 4 transmission, a guardinterval duration, a number of training fields (e.g., an STF, LTFs, andthe like). In some aspects, the master AP may configure the triggersignal to carry or otherwise convey an indication of whether thecoordinated MU transmission in stage 4 is uplink or downlink. In thedownlink scenario, the master AP and the neighboring AP(s) may generallyprovide downlink transmissions to their respective wireless station(s).In the uplink scenario, the master AP and the neighboring AP(s) maygenerally receive uplink transmissions from the respective wirelessstation(s). In some examples, the coordinated MU transmission may be acombination of downlink and uplink communications, e.g., some AP(s) maybe performing downlink transmissions while other AP(s) are receivinguplink transmissions. In some aspects, the trigger signal may beconfigured to indicate a maximum amount of interference that the masterAP can tolerate. This information may be usable by the neighboring AP(s)in setting their respective power control levels. In some aspects, themaster AP may configure the trigger signal to indicate the presence ofthe optional channel sounding stage (e.g., stage 3a). This may beperformed when the master AP schedules the neighboring AP(s) for channelsounding. In some aspects, the neighboring AP(s) may use thistransmission (e.g., the trigger signal) to perform/update theirrespective time and/or carrier frequency synchronizations with themaster AP.

In some aspects, the triggered transmission phase may include anoptional stage 3a where channel sounding is performed. In some aspects,this may include the master AP sending out synchronization frames toallow the neighboring AP(s) to synchronize and/or the masterAP/neighboring AP(s) to collect feedback, if needed, using explicitand/or implicit feedback mechanisms. In some aspects, this may includethe master AP configuring the trigger signal to indicate that channelsounding is to be performed between stage 3 and stage 4. The master APmay perform the channel sounding between itself and its associatedwireless station(s) during stage 3a while the neighboring AP(s) performchannel sounding between their self and their respective associatedwireless station(s). In some aspects, optional stage 3a may include,when needed, the master AP and neighboring AP(s) performing channelsounding per a schedule assigned by the master AP. In some aspects, themaster AP may set or otherwise configure the start and stop time forthis phase, e.g., such as in the stage 3 trigger transmission. When notneeded, master AP may set the duration for the optional stage 3a to azero value.

In some aspects, the triggered transmission phase may include stage 4 inwhich the MU transmission is performed. In some aspects, stage 4 mayinclude the master AP, in conjunction with the one or more neighboringAP(s) during the second portion of the TxOP, participating in the MUtransmission. That is, stage 4 may include the master AP performingdownlink transmissions to its associated wireless station(s) while theparticipating neighboring AP(s) perform downlink transmissions to theirrespective associated wireless station(s). In another example, stage 4may include the master AP receiving uplink transmissions from itsassociated wireless station(s) while the participating neighboring AP(s)receive uplink transmissions from their respective associated wirelessstation(s). In some aspects, stage 4 may include a mix of downlink anduplink transmissions during the transmission opportunities, e.g., one ormore AP(s) may be performing downlink transmissions while one or moreother AP(s) may be receiving uplink transmissions during the TxOP.

In some aspects, the master AP may transmit or otherwise provide anindication of a control channel assignment to its associated wirelessstation(s) that are participating in the MU transmission. Generally, thecontrol channel assignment may assign a control channel to each wirelessstation to use to determine the resource allocation for the MUtransmission between the master AP and the wireless station. Similarly,the one or more neighboring AP(s) may also transmit control channelassignment messages to each of its own associated wireless station(s)that are participating in the MU transmission. Generally, the wirelessstation(s) may use the control channel assignment to receive, in thebeginning of a data transmission portion of the MU transmission of stage4, the resource allocation for each station to use for the MUtransmission. In some aspects, the message or signal carrying orotherwise providing the indication of the control channel assignment maybe transmitted in the same or a different physical layer protocol dataunit than the data transmission of the MU transmission. In onenon-limiting example, the control channel assignment message may betransmitted in a preamble of the trigger signal of stage 4, e.g.,transmitted by each participating AP to begin an uplink MU transmissionfrom their respective wireless stations (which may also be referred toas a per-AP trigger signal). In another non-limiting example, thecontrol channel assignment message may be transmitted in a preamble ofthe data transmission. Accordingly, the master AP and neighboring AP(s)may participate in the MU transmission according to the control channelassignment.

FIG. 28 illustrates an example of a MU transmission scheme 2800 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 2800 may implement aspects of WLAN 100 and/or MUtransmissions scheme 2700. Aspects of the MU transmission scheme 2800may be implemented by an AP and/or a wireless station, which may beexamples of the corresponding devices described herein. Generally, theMU transmission scheme 2800 illustrates an example of a resource offerand request phase in accordance with aspects of the describedtechniques. Aspects of the MU transmission scheme 2800 may be associatedwith downlink and/or uplink transmissions during the MU transmission.

Generally, the resource offer and request phase may include the firststage 2805 (e.g., stage 1) and the second stage 2810 (e.g., stage 2).Broadly, stage 1 includes a distributed MU transmission invitation toparticipate transmitted by a master AP (e.g., a first AP). Generally,the master AP may obtain or otherwise secure access to a channel duringa TxOP and determine that extra resources are available for the MUtransmission during the TxOP. For example, the master AP may determinethat the resources associated with the TxOP (e.g., time, frequency,spatial, and the like) are more than the master AP needs to perform itstransmissions during the TxOP. Accordingly, in stage 1 the master AP maytransmit or otherwise provide an indication of an invitation or requestto participate in the MU transmission to one or more neighboring AP(s)(e.g., second or slave AP(s)). Generally, the invitation or request toparticipate may be provided in a first portion of the TxOP (e.g., theresource offer and request phase) and generally offers resources to theneighboring AP(s).

In some aspects, the contents of the distributed MU invitation toparticipate frame may serve to initiate or otherwise get the processstarted for the MU transmission and align symbols from variousneighboring AP(s) (e.g., provide a rough alignment between the master APand the neighboring AP(s)). In some aspects, the invitation toparticipate frame or message may carry or otherwise provide anindication of a variety of parameters, configurations, and the like. Insome aspects, the invitation to participate frame may carry anidentifier of AP(s) (e.g., a BSSID) that are being invited toparticipate in the MU transmission. In some aspects, the invitation toparticipate frame may carry a group identifier for a group of AP(s)(e.g., an identifier associated with the AP(s) that will beparticipating in the MU transmission). In some aspects, the invitationto participate frame may carry an indication of the resources availablefor the neighboring AP(s) (e.g., time, frequency, and/or spatialresources). In some aspects, the invitation to participate frame maycarry an indication of the duration of actual transmissions (such as aduration for which the resources are available), e.g., the TxOPduration. In some aspects, the invitation to participate frame may carrya resource allocation on a per-AP basis for subsequent frames (e.g., theintent to participate frame and/or a control channel assignment frame).In some aspects, the invitation to participate frame may carry anindication of the transmit power of the transmitting AP (e.g., themaster AP) and/or a tolerable interference/RSSI level for OBSStransmissions (which may be combined into a single entity as well). Insome aspects, the invitation to participate frame may carry anindication of the number of long training fields (LTF) symbols for theMU transmission. All AP(s) participating in the MU transmission mayfollow the indication of the number of symbols for downlink and/or relaythis information to their respective wireless station(s) in theirtrigger signals for uplink. In some aspects, the invitation toparticipate frame may carry an indication of a midamble periodicity. Insome aspects, the invitation to participate frame may carry anindication of a guard interval duration/LTF type (e.g., 1×, 2×, or 4×)being used during the MU transmission. Again, all AP(s) participating inthe MU transmission may follow the indication for downlink and/or relaythis information to the respective wireless station(s) in their triggersignals for uplink.

Broadly, stage 2 includes intent to participate frame(s) from theneighboring AP(s) that signals their intent to participate in the MUtransmission. For example, the neighboring AP(s) may reply to theinvitation or request to participate with a request for resources in theintent to participate frame(s). In the example MU transmission scheme2800, AP 2, AP 3, and AP 4 transmit or otherwise provide the indicationof the intent to participate to the master AP, with each indication ofintent to participate signaling a request for resources by therespective neighboring AP. In some aspects, the intent to participateframes from the neighboring AP(s) may be transmitted or otherwiseprovided according to a variety of manners.

In some aspects, only the master AP is a target of the intent toparticipate frame. In some aspects, the intent to participate framesfrom each of the neighboring AP(s) may be provided one AP at a time(e.g., according to a scheduled transmission, based on the neighboringAP being polled by the master AP, and the like). In some aspects, uplinkmultiple user multiple input/multiple output (MU-MIMO) and/or uplinkorthogonal frequency division multiple access (OFDMA) may be used tosend the intent to participate frames to the master AP. In this example,the resource allocation for transmission of the intent to participateframes may be provided in the invitation or request to participate framefrom the master AP. In some aspects, the intent to participate frame maycarry or otherwise convey an indication of the resources being requestedby the neighboring AP(s) (e.g., slave AP(s)). The resource request maybe explicit and/or implicit, e.g., requested indirectly through otherparameters such as queue lengths, priority, and the like.

FIG. 29 illustrates an example of a MU transmission scheme 2900 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 2900 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700 and/or 2800. Aspects of the MU transmissionscheme 2900 may be implemented by an AP and/or a wireless station, whichmay be examples of the corresponding devices described herein.Generally, the MU transmission scheme 2900 illustrates an example of aresource offer and request phase in accordance with aspects of thedescribed techniques. Aspects of the MU transmission scheme 2900 may beassociated with downlink and/or uplink transmissions during the MUtransmission.

Generally, the resource offer and request phase may include the firststage 2905 (e.g., stage 1) and a second stage (e.g., stage II), but withthe second stage being broken up into separate frames. Broadly, stage 1includes a distributed MU transmission invitation to participatetransmitted by a master AP (e.g., a first AP). Generally, the master APmay obtain or otherwise secure access to a channel during a TxOP anddetermine that extra resources are available for the MU transmissionduring the TxOP. For example, the master AP may determine that theresources associated with the TxOP (e.g., time, frequency, spatialresources) are more than the master AP needs to perform itstransmissions during the TxOP. Accordingly, in stage 1 the master AP maytransmit or otherwise provide an indication of an invitation or requestto participate in the MU transmission to one or more neighboring AP(s)(e.g., second or slave AP(s)). Generally, the invitation or request toparticipate may be provided in a first portion of the TxOP (e.g., theresource offer in request phase) and generally offers resources to theneighboring AP(s).

Broadly, stage 2 includes two intent to participate frame(s) from theneighboring AP(s) that signals their intent to participate in the MUtransmission. For example, the first frame 2910 may include theneighboring AP(s) replying to the invitation or request to participatewith a request for resources in the intent to participate first frame2910. That is, the first frame 2910 generally carries or otherwiseprovides an indication of the request for resources by AP 2, AP 3, andAP 4 to the master AP. The second frame 2915 may be targeted to thewireless station(s) associated with the transmitting AP and generallyprimes the wireless station(s) for the MU transmission.

That is, MU transmission scheme 2900 generally breaks stage 2 of thedescribed techniques into 2 parts (2 frames) where both the master APand wireless station(s) are targets that are signaled using separateprotocol data units. The first part (e.g., the first frame 2910 or firstprotocol data unit) may be transmitted or otherwise provided from theneighboring AP(s) to the master AP. The first frame 2910 may betransmitted otherwise provided sequentially and/or as a regular triggerbased (TB) protocol data unit to convey the resource request (e.g.,uplink OFDMA and/or uplink MU-MIMO). Generally, the first frame 2910carries or otherwise provides the indication of the resource requestfrom the neighboring AP(s) to the master AP.

Generally, the second part (e.g., the second frame 2915) may generallybe transmitted or otherwise provided to wireless stations (e.g.,wireless station(s) associated with the respective neighboring AP thatare participating in the MU transmission). In some aspects, the secondframe 2915 may be transmitted redundantly. For example, the second frame2915 may be transmitted in every 20 MHz channel, where the informationis duplicated within each 20 MHz channel. In some aspects, every AP (themaster AP as well as each participating neighboring AP) may transmit thesecond frame 2915 in every 20 MHz channel. Broadly, the second frame2915 primes the wireless station(s) for measuring channel power of agroup configured trigger signal and moving to their respective channels.In some aspects, the second frame 2915 may be transmitted when the MUtransmission involves uplink transmissions from the wireless stations.In some aspects, the second frame 2915 may carry or otherwise convey anindication of the list of the slave wireless stations participating inthe MU transmission (e.g., an identifier for each wireless stationand/or a group identifier associated with the wireless stations).

FIG. 30 illustrates an example of a MU transmission scheme 3000 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3000 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, and/or 2900. Aspects of the MUtransmission scheme 3000 may be implemented by an AP and/or a wirelessstation, which may be examples of the corresponding devices describedherein. Generally, the MU transmission scheme 3000 illustrates anexample of a stage 2 transmission in the resource offer and requestphase in accordance with aspects of the described techniques. Aspects ofthe MU transmission scheme 3000 may be associated with downlink and/oruplink transmissions during the MU transmission. More specifically, MUtransmission scheme 3000 illustrates an example format for an intent toparticipate transmission from one or more neighboring AP(s) to a masterAP in response to an invitation or request to participate in a MUtransmission.

As discussed, one option for transmission of the intent to participate(e.g., the intent to participate transmission) may include the one ormore of the neighboring AP(s) transmitting the intent to participate inparallel, where each of the neighboring AP(s) may transmit a uniqueintent to participate indication and/or may transmit a similar intent toparticipate indication. One benefit of this is that it down selects thewireless stations to achieve power savings and primes the wirelessstation(s) for listening to a subsequent frame from the master AP forpower control. Another option for transmission of the intent toparticipate may include the one or more neighboring AP(s) transmittingthe intent to participate one neighboring AP at a time (e.g., accordingto a schedule or based on a polling signal from the master AP). Forexample, an OFDMA signal may be sent to the master AP and the wirelessstations, with the resource allocation for transmission of the intent toparticipate being provided in the invitation or request to participateframe. In this instance, the preamble of the frame may be configured toindicate or otherwise inform the wireless station(s) about the resourceallocation for this frame.

As discussed, the resource offer and request phase may include the firststage (e.g., stage 1) that includes a and master AP transmitting orotherwise providing a request or invitation to participate in the MUtransmission and a second stage (e.g., stage II) where the neighboringAP(s) provide the indication of the intent to participate to the masterAP. MU transmission scheme 3000 illustrates one example configuration inwhich the intent to participate indication is transmitted from theneighboring AP(s), such as from AP 2 and AP 3, in parallel.

Broadly, MU transmission scheme 3000 illustrates an example where themaster AP allocates 40 MHz each to two neighboring AP(s) (AP 2 and AP 3)for transmitting the intent to participate frame. Aspects of the MUtransmission scheme 3000 are similar to a downlink MU-PPDU (beingtransmitted by multiple AP(s)) with the payload sent in an OFDMAfashion, and indicates to recipients a payload location in frequency. Inparticular, each of AP 2 and AP 3 may transmit on each 20 MHz channel.Generally, the information in each of the frames up to the SIG-B commonframe 3015 is the same across each 20 MHz channel from each of AP 2 andAP 3, such as in a broadcast transmission. Next, each of AP 2 and AP 3(on each 20 MHz channel) may transmit a SIG-B frame 3020 for AP 2 and aSIG-B frame 3025 for AP 3. That is, instead of a per-user (e.g.,wireless station) SIG-B field, the MU transmission scheme 3000 includesa per-AP SIG-B frame for each of AP 2 and AP 3. In some aspects, theSIG-B frame 3020 for AP 2 may carry or otherwise convey an indication ofan identifier for AP 2, which may be recognizable by wireless station(s)associated with AP 2. Similarly, the SIG-B frame 3025 for AP 3 may carryor otherwise convey an indication of an identifier for AP 3, which maybe recognizable by wireless station(s) associated with AP 3.

Following the per-AP SIG frames, AP 2 may transmit a STF and LTF 3030followed by an intent to participate payload 3035 for AP 2. Similarly,AP 3 may transmit (on its respective 40 MHz channel) a STF and LTF 3040followed by an intent to participate payload 3045 for AP 3. Asdiscussed, the contents of each intent to participate payload mayinclude a list (e.g., identifiers) of the wireless station(s) associatedwith the respective neighboring AP and/or an indication of the resourcesbeing requested by the neighboring AP.

FIGS. 31A-31C illustrate examples of a MU transmission scheme 3100 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3100 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, 2900, and/or 3000. Aspects of the MUtransmission scheme 3100 may be implemented by an AP and/or a wirelessstation, which may be examples of the corresponding devices describedherein. Generally, the MU transmission scheme 3100 illustrates variousexamples of scheduling approaches for a stage 2 transmission in theresource offer and request phase in accordance with aspects of thedescribed techniques. Aspects of the MU transmission scheme 3100 may beassociated with downlink and/or uplink transmissions during the MUtransmission.

As discussed, the described MU transmission schemes may includetransmission of an intent to participate from one or more neighboringAP(s) (such as AP 2, AP 3, and AP 4) to a master AP (such as AP 1).Generally, each of the scheduling approaches illustrated in MUtransmission scheme 3100 may be implemented in response to theneighboring AP(s) (or slave AP(s)) receiving the invitation or requestto participate in the MU transmission from the master AP. Referringfirst to FIG. 31A, in one example the intent to participatetransmissions may be provided from the neighboring AP(s) in parallel.For example, AP 2 may transmit its intent to participate message 3105 inconjunction with AP 3 transmitting its intent to participate message3110 and AP 4 transmitting its intent to participate message 3115.Aspects of the simultaneous transmission may be achieved using varioustechniques to distinguish the respective intent to participate messageby the master AP. Example techniques to distinguish the respectiveintent to participate message include, but are not limited to, frequencydiversity, spatial domain diversity, code division diversity, and/or anyother orthogonal technique. In some aspects, the simultaneous orparallel transmission may utilize either MU-MIMO and/or OFDMA techniquesto distinguish the intent to participate messages from the respectiveneighboring AP(s).

Referring next to FIG. 31B, the intent to participate transmissions maybe provided from the neighboring AP(s) according to a scheduledtransmission. As discussed, the invitation or request to participatemessage transmitted by the master AP may provide an indication of one ormore resources and/or configuration for the neighboring AP(s) to respondwith their respective intent to participate messages. In the exampleillustrated in FIG. 31B, the indication provided in the request orinvitation to participate may schedule each of the neighboring AP(s) totransmit their respective intent to participate message at a differenttime (e.g., may utilize time diversity to help distinguish between therespective intent to participate messages). Accordingly, AP 2 maytransmit its intent to participate message 3105 during a first timeperiod, AP 3 may transmit its intent to participate message 3110 duringa second time period, an AP 3 may transmit its intent to participatemessage 3115 during an third time period.

Referring next to FIG. 31C, the intent to participate transmissions maybe provided from the neighboring AP(s) according to a polledtransmission. For example, the master AP may configure the invitation orrequest to participate message to indicate that the polling transmissionscheme will be utilized by the neighboring AP(s) and, in some examples,provide various configuration information for the polling transmissions(e.g., such as an order, timing, and the like). Accordingly, the masterAP may transmit a polling signal 3120 that signals AP 2 to transmit itsintent to participate message 3105. The master AP may transmit a pollingsignal 3125 the signals AP 3 transmit its intent to participate message3110. And finally, the master AP may transmit a polling signal 3130 thatsignals AP 4 to transmit its intent to participate message 3115. In someaspects, the polling signal 3120 may be implicit for AP 2.

FIG. 32 illustrates an example of a MU transmission scheme 3200 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3200 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, 2900, 3000, and/or 3100. Aspects ofthe MU transmission scheme 3200 may be implemented by an AP and/or awireless station, which may be examples of the corresponding devicesdescribed herein. Generally, the MU transmission scheme 3200 illustratesan example configuration for the triggered MU transmission phase inaccordance with aspects of the described techniques. Aspects of the MUtransmission scheme 3200 may be associated with downlink and/or uplinktransmissions during the MU transmission.

Broadly, MU transmission scheme 3200 illustrates a high-level canonicalblock configuration for the triggered MU transmission phase that isapplicable to downlink and/or uplink transmissions during the MUtransmission. The features illustrated with respect to the MUtransmission scheme 3200 may be performed following the resource offerand request phase, as is discussed above. Generally, the MU transmissionscheme 3200 begins by the master AP transmitting a trigger signal 3205to one or more neighboring AP(s) that carries or otherwise provides anindication of a set of resources for each neighboring AP to use duringthe MU transmission. That is, the master AP may send the final resourceallocations in the distributed MU group in the configuration frame whichacts as a trigger from the perspective of the neighboring AP(s). In someaspects, the trigger signal 3205 may be transmitted during an initialperiod of the second portion of the TxOP. In some aspects, the triggersignal 3205 may additionally be transmitted in a no data packetannouncement (NDPA) frame of the optional sound phase. In some aspects,the trigger signal 3205 may ensure cross-AP synchronization and symbolalignment for the MU transmission.

In some aspects, the trigger signal 3205 may carry or convey anindication of a variety of parameters. For example, the trigger signal3205 may carry or convey an indication of the final resource allocationfor the neighboring AP(s) (e.g., AP 2, AP 3, and AP 4). In some aspects,the trigger signal 3205 may carry or convey an indication of anidentifier for the neighboring AP(s) (e.g., BSSID). In some aspects, thetrigger signal 3205 may carry or convey an indication of a group ID thatis associated with the neighboring AP(s) and the master AP (e.g., theAP(s) participating in the MU transmission). In some aspects, thetrigger signal 3205 may carry or convey an indication of the duration ofthe actual transmissions (e.g., a duration or period of the TxOP). Insome aspects, the trigger signal 3205 may carry or convey an indicationof the transmit power of the master AP, a tolerable or allowableinterference level that the master AP may support, and RSSI level forcross-BSS transmissions, and the like. In some aspects, such variablesmay be combined into a single entity (e.g., a single field or bitmap).In some aspects, the trigger signal 3205 may carry or convey anindication of a number of high efficiency (HE)-LTF symbols and HE-SIG-Bsymbols for the TxOP. All AP(s) participating in the MU transmission mayfollow this indication for the downlink and/or relay this information totheir respective wireless station(s) in their per-AP trigger frame 3215for uplink. In some aspects, the trigger signal 3205 may carry or conveyan indication of the trigger frame lengths. In some aspects, the triggersignal 3205 may carry or convey an indication of a midamble periodicity.In some aspects, the trigger signal 3205 may carry or convey anindication of a guard interval duration and/or an LTF type being used.Again, each AP participating the MU transmission may follow thisinformation for the downlink and/or relay this information to theirrespective wireless station(s) for the uplink.

In some aspects, the trigger signal 3205 may be followed by an optionalsounding phase. In some aspects, this may include sequential soundingwhere one NDP per-AP use the sounding one AP at a time. This mayleverage various sounding sequences, but with certain tweaks (e.g., theNDPA may address even OBSS wireless stations). In some aspects, this mayinclude joint sounding using one NDP to sound transmit to all the AP(s).This may result in some reduction in overhead. The NDPs may be timemultiplexed, code multiplex (e.g., P matrix) and/or frequencymultiplexed among the transmit chains of all AP(s). In some aspects,this may include implicit sounding, e.g., using separate uplink NDPs perwireless station or a joint uplink NDP from all wireless stations.

The optional sounding phase may be followed by a per-AP SIG/controlchannel assignment frame 3210. In some aspects, the per-AP SIG/controlchannel assignment frame 3210 may provide an indication of a channelallocation for the downlink case and/or uplink case. In one option, thismay be signaled in a separate frame (as is shown), combined with thetrigger signal 3205, and/or may be a part of the actual downlinktransmission.

Although the per-AP SIG/control channel assignment frame 3210 isillustrated in FIG. 32 as being sent in a single frame, in some aspectsthis may be divided into separate frames for each AP. This mayfacilitate moving the wireless stations of their respective AP to switchchannels for the MU transmission. Broadly, each frame may carry orconvey an indication of the multiple of the 20 MHz channels of thewireless station(s) corresponding to the sending AP (e.g., based on theBSSID) that the wireless station(s) are to monitor. In some aspects,this may be a repeat of the per-AP resource allocation indicated in thetrigger signal 3205. The separate per-AP SIG/control channel assignmentframe 3210 may be separated into multiple frames using varyingtechniques. For example, OFDMA techniques may be utilized for the per-APSIG/control channel assignment frame 3210. For example, the resourceallocation for the frame may be carried or otherwise conveyed in one ormore of the frames that precede the per-AP SIG/control channelassignment frame 3210, the invitation to participate frame for themaster AP and/or the trigger signal 3205 from the master AP. Anotherexample may include identical content being signaled in each band (e.g.,each 20 MHz channel), with each AP sending the control channelinformation for all of the AP(s) participating in the MU transmission onall of the channels. For example, this may be duplicated across each 10MHz channel, 20 MHz channel, 40 MHz channel, and the like. While thisoption may slightly increase overhead, and may also provide for easierconfiguration.

This may be followed by per-AP trigger frames 3215 from each AP.Generally, each per-AP trigger frame 3215 may be transmitted by the allof the AP(s) that have detailed per-wireless station resourceallocations. In some aspects, the per-AP trigger frame 3215 may beutilized in an uplink transmission scenario, rather than a downlinktransmission scenario.

This may be followed by the downlink or uplink TB waveform 3220, e.g.,the actual data transmission portion of the MU transmission. For thedownlink case, the detailed per-wireless station resource allocationsmay happen in the actual downlink or uplink TB waveform 3220. In someaspects, the location of the per-AP trigger frame 3215 and/or thedownlink or uplink TB waveform 3220 in the frequency domain may besignaled in the control channel assignment frame (e.g., the per-APSIG/control channel assignment frame 3210).

FIG. 33 illustrates an example of a MU transmission scheme 3300 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3300 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, 2900, 3000, 3100, and/or 3200. Aspectsof the MU transmission scheme 3300 may be implemented by an AP and/or awireless station, which may be examples of the corresponding devicesdescribed herein. Generally, the MU transmission scheme 3300 illustratesan example configuration for stage 4 of the triggered MU transmissionphase in accordance with aspects of the described techniques. Aspects ofthe MU transmission scheme 3300 may be associated with downlink and/oruplink transmissions during the MU transmission.

Broadly, MU transmission scheme 3300 illustrates an example where theper-AP SIG/control channel assignment frame (such as the per-APSIG/control channel assignment frame 710 of FIG. 7) is carried in thedownlink transmission itself. That is, the MU transmission scheme 3300illustrates an example protocol data unit format with the controlchannel allocation happening within the protocol data unit. Generallythis may begin with each AP participating in the MU transmissiontransmitting or otherwise providing an L-STF field 3305, and L-LTF field3310, an L-SIG field 3315, a marker field 3320, a SIG-0 field 3325, anSTF-0 field 3330, an LTF-0 field 3335, a SIG-A field 3340, and a SIG-Bfield 3345. In some aspects, the L-STF field 3305, and L-LTF field 3310,an L-SIG field 3315, a marker field 3320, a SIG-0 field 3325, an STF-0field 3330, and the LTF-0 field 3335 may be transmitted in theduplicated manner, such as in every 20 MHz channel associated with theTxOP. That is, every AP participating in the MU transmission maytransmit the same information in these fields on every 20 MHz channel.In some aspects, the EHT indication may be carried or conveyed in themarker field 3320. In some aspects, the SIG-0 field 3325 may carry orconvey a particular AP(s) SIG-AB information. For example, in one optionthe SIG-0 field 3325 may carry or convey both data and the controlchannel location. In another option, the SIG-0 field 3325 may only carryor convey the control channel location. One benefit of this option maybe that there is no coupling between the control channel location andthe data bandwidths in a pre-SIG portion of the preamble. In someexamples, the SIG-0 field 3325 may use a group identifier to conveyallocations (e.g., an AP group identifier to convey the indication ofthe location of the control channels).

In some aspects the SIG-0 field 3325, the STF-0 field 3330, and theLTF-0 field 3335 may be considered as a pre-SIG section that conveys orindicates the location of the control channels and provides a channelestimation opportunity for all the channels before the wireless stationstunes to the relevant SIG-AB channels. In some aspects the SIG-A field3340 may be duplicated only in every AP(s) allocated bandwidth. Someaspects, the SIG-B field 3345 may carry or convey the per-wirelessstation allocation and may have different content in some or all of the20 MHz channels. In other aspects, the SIG-B field 3345 may beduplicated in an alternating fashion amongst the 20 MHz channels.

In some aspects, each AP may transmit an STF field 3350 followed by anLTF field 3355 and user data 3360 to complete the MU transmission. It isto be understood that each user data 3360 field may be associated withdifferent users (e.g., different wireless stations) and/or with the sameuser.

In some aspects, the L-STF field 3305, L-LTF field 3310, L-SIG field3315, marker field 3320, SIG-0 field 3325, STF-0 field 3330, LTF-0 field3335, SIG-A field 3340, and SIG-B field 3345 may be considered thepreamble for the stage 4 transmission of the MU transmission. In someaspects, MU transmission scheme 3300 may also be used for a widebandtransmission from a single AP. For example, this configuration may allowthe AP to handle wireless stations with different bandwidthcapabilities, as it offers a way to park groups of wireless stations todifferent “20 MHz-multiple” channels, e.g., in a 320 MHz protocol dataunit, this configuration provides a mechanism to move a certain group ofwireless stations which are 80 MHz capable to a certain “20MHz-multiple” channel. In some aspects, this may also enable the SIGstructure to depart from the 802.11ax amendment's [1 2 1 2] frequencyrepetition structure of SIG-B for wider bandwidths, thereby allowing formore parallelization and therefore lowering overhead.

FIG. 34 illustrates an example of a MU transmission scheme 3400 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3400 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, 2900, 3000, 3100, 3200, and/or 3300.Aspects of the MU transmission scheme 3400 may be implemented by an APand/or a wireless station, which may be examples of the correspondingdevices described herein. Generally, the MU transmission scheme 3400illustrates an example configuration for the triggered MU transmissionphase in accordance with aspects of the described techniques. Aspects ofthe MU transmission scheme 3400 may be associated with downlink and/oruplink transmissions during the MU transmission.

In some aspects, MU transmission scheme 3400 illustrates one exampleconfiguration for a triggered MU transmission phase. This may include astage 4 transmission where all AP(s) that participate in the MUtransmission are performing the MU transmission during the secondportion (e.g., the triggered transmission phase) of the TxOP. Generally,in beginning of this stage all of the participating AP(s) may jointlyindicate to all of the wireless stations the channel to which to receivetheir respective SIG fields. This is illustrated in FIG. 34 as theper-AP SIG channel assignment 3405, which may also be referred to aseach AP participating in the MU transmission performs the MUtransmission to the respective wireless stations, or vice versa. In someaspects, there may be an optional gap in time after the per-AP SIGchannel assignment 3405 to allow time for bandwidth-limited wirelessstations to retune to the correct channel.

After the optional gap in time, the participating AP(s) may make anynecessary resource unit assignments to their respective wirelessstations. In some aspects, these resource assignments may be specific toa channel for each participating AP (e.g., the master AP (AP 1) and theslave AP(s) (AP 2 and AP 3)). This may generally be a part of thecoordinated MU transmission 3410, 3415, and 3420 from the perspective ofthe participating AP(s). In the example where the coordinated a MUtransmission is downlink, all participating AP(s) transmit on their dataon their assigned channels and according to their specified protocoldata unit structure. In the example where the coordinated a MUtransmission is uplink, all participating wireless stations transmit ontheir assignment channel ports/resource unit according to theirassignments. Accordingly, the coordinated a MU transmission 3410, 3415,and 3420 are the actual data transmissions performed during the MUtransmission.

Thus, MU transmission scheme 3400 begins with the per-AP SIG channelassignment 3405 in which all the AP(s) transmit their respective SIGchannel assignments. In some aspects, these assignments were made instage 3 (e.g., in the trigger signal) by the master AP, but not all ofthe wireless stations may receive that message. Accordingly, all of theparticipating AP(s) transmit the per-AP SIG channel assignment 3405 inorder for all of their respective wireless stations to receive thisinformation to determine which channel to receive their SIG fields(along with the prior STFs and LTFs). After the optional time gap thetransmission begins with the STF, LTFs, and SIG field. This enables theAP(s) to communicate the resource unit assignments to the respectivewireless stations.

FIG. 35 illustrates an example of a MU transmission scheme 3500 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3500 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, 2900, 3000, 3100, 3200, 3300, and/or3400. Aspects of the MU transmission scheme 3500 may be implemented byan AP and/or a wireless station, which may be examples of thecorresponding devices described herein. Generally, the MU transmissionscheme 3500 illustrates an example downlink configuration for the MUtransmission scheme in accordance with aspects of the describedtechniques.

In some aspects, MU transmission scheme 3500 generally illustrates anexample downlink configuration where a master AP (e.g., a first AP orAP 1) and one or more slave AP(s) (e.g., one or more neighboring orsecond AP(s), such as AP 2, AP 3, and AP 4) participate in a downlink MUtransmission to their respective wireless station(s). Generally, MUtransmission scheme 3500 may divided into a first portion of the TxOPthat includes a resource offer and request phase and a second portion ofthe TxOP that includes a triggered transmission phase. The first portionof the TxOP typically includes a stage 1 where the master AP transmitsan invitation or request to participate 3505 in the MU transmissionduring the second portion (e.g., the triggered transmission phase) ofthe TxOP. Generally, the invitation or request to participate 3505 istransmitted to one or more neighboring AP(s) as an offer or invitationfor the neighboring AP(s) to participate in the MU transmission.Neighboring AP(s) that receive the invitation or request to participate3505 may determine whether or not they have data to communicate duringthe TxOP. If not, the neighboring AP(s) may simply ignore or disregardthe request or invitation to participate 3505. If so, the first portionof the TxOP may proceed to stage 2 where the neighboring AP(s) (whichalso may be referred to as slave AP(s)) transmit an indication of anintent to participate 3510 in the MU transmission. In some aspects, theintent to participate 3510 may carry or otherwise convey an indicationof a request for resources for the respective neighboring AP(s). Forexample, the intent to participate 3510 may carry or indicate anexplicit request for resources (e.g., such as a request for specifictime/frequency/spatial resources) and/or an implicit request forresources (e.g., such as an indication of a queue size).

MU transmission scheme 3500 may proceed to the trigger transmissionphase (e.g., the second portion of the TxOP) where the master APtransmits a trigger signal 3515 to the neighboring AP(s) that carries orotherwise conveys an indication of a set of resources for each of theneighboring AP(s) to use for the MU transmission. In some aspects, thismay be considered the final per-AP resource allocation. In some aspects,this information may additionally be provided in an NDPA of an optionalsounding phase that follows the trigger signal 3515. In some aspects,transmission of the trigger signal 3515 may be referred to as stage 3and the optional sounding phase may be referred to as stage 3a.

MU transmission scheme 3500 may proceed next to the MU transmission,which may include a per-AP SIG/control channel assignment frame 3520 andthe data transmission 3525. That is, the example configurationillustrated in MU transmission scheme 3500 includes a control channelassignment frame (e.g., the per-AP SIG/control channel assignment frame3520) that is separate from the data transmission 3525. In the downlinkexample, the data transmission 3525 may include an 802.11ac waveform, an802.11ax waveform, an HE waveform, and the like. In some aspects, thelocation of the data transmission 3525 in frequency may be signaled inthe control channel assignment (e.g., the per-AP SIG/control channelassignment frame 3520). Although illustrated as being separate, in someaspects the per-AP SIG/control channel assignment frame 3520 may becombined with the downlink waveform (e.g., the data transmission 3525 orpre-SIG).

FIG. 36 illustrates an example of a MU transmission scheme 3600 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. In some examples, MUtransmission scheme 3600 may implement aspects of WLAN 100 and/or MUtransmissions schemes 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400,and/or 3500. Aspects of the MU transmission scheme 3600 may beimplemented by an AP and/or a wireless station, which may be examples ofthe corresponding devices described herein. Generally, the MUtransmission scheme 3600 illustrates an example uplink configuration forthe MU transmission scheme in accordance with aspects of the describedtechniques.

In some aspects, MU transmission scheme 3600 generally illustrates anexample uplink configuration where a master AP (e.g. a first AP or AP 1)and one or more slave AP(s) (e.g., one or more neighboring or secondAP(s), such as AP 2, AP 3, and AP 4) participate in an uplink MUtransmission from their respective wireless stations. Generally, MUtransmission scheme 3600 may divided into a first portion of the TxOPthat includes a resource offer and request phase and a second portion ofthe TxOP that includes a triggered transmission phase. The first portionof the TxOP typically includes a stage 1 where the master AP transmitsan invitation or request to participate 3605 in the MU transmissionduring the second portion (e.g., a triggered transmission phase) of theTxOP. Generally, the invitation or request to participate 3605 istransmitted to one or more neighboring AP(s) as an offer or invitationfor the neighboring AP(s) to participate in the MU transmission.Neighboring AP(s) that receive the invitation or request to participate3605 may determine whether or not they have data to communicate fromtheir respective wireless stations during the TxOP. If not, theneighboring AP(s) may simply ignore or disregard the request orinvitation to participate 3605. If so, the first portion of the TxOP mayproceed to stage 2 where the neighboring AP(s) (which also may bereferred to as slave AP(s)) transmit an indication of an intent toparticipate 3610 in the MU transmission. In some aspects, the intent toparticipate 3610 may carry or otherwise convey an indication of arequest for resources for the respective neighboring AP. For example,the intent to participate 3610 may carry or indicate an explicit requestfor resources (e.g., such as a request for specifictime/frequency/spatial resources) and/or an implicit request forresources (e.g., such as an indication of a queue size).

In a downlink scenario, the intent to participate 3610 is generallytargeted to the master AP. However, in an uplink scenario the intent toparticipate 3610 may be targeted to the master AP and one or more of theassociated wireless stations that are associated with the neighboringAP. This may enable down selecting the wireless stations that need tomonitor the RSSI of the trigger signal 3615. As discussed previously, insome examples the intent to participate 3610 may be provided in a singleprotocol data unit or may be set separated into a first and secondprotocol data unit by the neighboring AP(s).

MU transmission scheme 3600 may proceed to the trigger transmissionphase (e.g., the second portion of the TxOP) where the master APtransmits a trigger signal 3615 to the neighboring AP(s) that carries orotherwise conveys an indication of a set of resources for each of theneighboring AP(s) to use for the MU transmission. In some aspects, thismay be considered the final per-AP resource allocation. In some aspects,this information may additionally be provided in an NDPA of an optionalsounding phase that follows the trigger signal 3615. In some aspects,transmission of the trigger signal 3615 may be referred to as stage 3and the optional sounding phase may be referred to as stage 3a.

MU transmission scheme 3600 may proceed next to the MU transmission,which may include a per-AP SIG/control channel assignment frame 3620, aper-AP trigger 3625, and the data transmission 3630. That is, theexample configuration illustrated in MU transmission scheme 3600includes a control channel assignment frame (e.g., the per-APSIG/control channel assignment frame 3620) that is separate from theper-AP trigger 3625 and the data transmission 3630. In some aspects, theper-AP SIG/control channel assignment frame 3620 and the per-AP trigger3625 may be combined. In some aspects, the location in frequency of theper-AP trigger 3625 may be signaled or otherwise conveyed in the per-APSIG/control channel assignment frame 3620. In some aspects, the locationof the per-AP trigger 3625 frames (in frequency) may be carried orotherwise conveyed in the separate frame indicating the control channelinformation is transmitted before the per-AP trigger 3625 (e.g., such asthe per-AP SIG/control channel assignment frame 3620) and/or as apreamble in the per-AP trigger 3625. In some aspects, the wirelessstation control channel assignment may be provided in the preamble ofthe trigger signal 3615 and/or the per-AP trigger 3625. Accordingly, theper-AP trigger 3625 allows for a detailed per-wireless stationallocation to be provided by the respective AP. In the uplink example,the data transmission 3630 may include a 802.11ac waveform, an 802.11axwaveform, a HE waveform, and the like. In some aspects, the location ofthe data transmission 3630 in frequency may be signaled in the controlchannel assignment (e.g., the per-AP SIG/control channel assignmentframe 3620).

FIG. 37 shows a block diagram 3700 of a device 3705 that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure. The device 3705 may be an example orimplement aspects of device 905, device 1005, device 1205, or an AP asdescribed herein. The device 3705 may include a receiver 3710, acommunications manager 3715, and a transmitter 3720. The device 3705 mayalso include a processor. Each of these components may be incommunication with one another (e.g., via one or more buses). In someaspects, each of these components may, collectively or in anycombination, be considered a wireless modem, or a subset of a wirelessmodem. In some aspects, the wireless modem may be a component of awireless chip or chipset.

The receiver 3710 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to protocolsfor multi-AP coordinated MU transmissions, etc.). Information may bepassed on to other components of the device. The receiver 3710 may be anexample of aspects of the transceiver 4020 described with reference toFIG. 40. The receiver 3710 may utilize a single antenna or a set ofantennas.

The communications manager 3715 may transmit, to a second AP and duringa first portion of a TxOP, a request to participate in a MU transmissionduring a second portion of the TxOP, receive, from the second AP andduring the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission, transmit, during aninitial period of the second portion of the TxOP, a trigger signal tothe second AP indicating a set of one or more resources for the secondAP during the MU transmission, and participate, in conjunction with thesecond AP and during the second portion of the TxOP, in the MUtransmission. The communications manager 3715 may also receive, from afirst AP and during a first portion of a TxOP, a request to participatein a MU transmission during a second portion of the TxOP, transmit, tothe first AP and during the first portion of the TxOP, an indication ofintent to participate in the MU transmission during the second portionof the TxOP, the indication of intent including a resource request ofthe second AP for participation in the MU transmission, receive, duringan initial period of the second portion of the TxOP, a trigger signalfrom the first AP indicating a set of one or more resources for thesecond AP during the MU transmission, and participate, in conjunctionwith the first AP and during the second portion of the TxOP, in the MUtransmission. The communications manager 3715 may be an example ofaspects of the communications manager 4010 described herein.

The communications manager 3715, or its sub-components, may beimplemented in hardware, code (e.g., software or firmware) executed by aprocessor, or any combination thereof. If implemented in code executedby a processor, the functions of the communications manager 3715, or itssub-components may be executed by a general-purpose processor, a DSP, anapplication-specific integrated circuit (ASIC), a FPGA or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described in the present disclosure.

The communications manager 3715, or its sub-components, may bephysically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations by one or more physical components. In some examples, thecommunications manager 3715, or its sub-components, may be a separateand distinct component in accordance with various aspects of the presentdisclosure. In some examples, the communications manager 3715, or itssub-components, may be combined with one or more other hardwarecomponents, including but not limited to an input/output (I/O)component, a transceiver, a network server, another computing device,one or more other components described in the present disclosure, or acombination thereof in accordance with various aspects of the presentdisclosure.

The transmitter 3720 may transmit signals generated by other componentsof the device. In some examples, the transmitter 3720 may be collocatedwith a receiver 3710 in a transceiver module. For example, thetransmitter 3720 may be an example of aspects of the transceiver 4020described with reference to FIG. 40. The transmitter 3720 may utilize asingle antenna or a set of antennas.

In some examples, the communications manager 3715 may be an example of awireless modem implemented as a separate chipset or as a component of asystem on chip (SoC), and the receiver 3710 and transmitter 3720 mayinclude analog components (e.g., amplifiers, filters, phase shifters,antennas, etc.) to facilitate the receipt and transmission of wirelesssignals. The communications manager 3715 may obtain and decode signalsreceived wirelessly from the receiver 3710 via a receive interface. Thecommunications manager 3715 also may output signals for wirelesstransmission by the transmitter 3720 over a transmit interface.

FIG. 38 shows a block diagram 3800 of a device 3805 that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure. The device 3805 may be an example ofaspects of a device 3705 or a AP 105 as described herein. The device3805 may include a receiver 3810, a communications manager 3815, and atransmitter 3840. The device 3805 may also include a processor. Each ofthese components may be in communication with one another (e.g., via oneor more buses).

The receiver 3810 may receive information such as packets, user data, orcontrol information associated with various information channels (e.g.,control channels, data channels, and information related to protocolsfor multi-AP coordinated MU transmissions, etc.). Information may bepassed on to other components of the device. The receiver 3810 may be anexample of aspects of the transceiver 4020 described with reference toFIG. 40. The receiver 3810 may utilize a single antenna or a set ofantennas.

The communications manager 3815 may be an example of aspects of thecommunications manager 3715 as described herein. The communicationsmanager 3815 may include a request to participate manager 3820, anintent to participate manager 3825, a trigger signal manager 3830, and aMU transmission manager 3835. The communications manager 3815 may be anexample of aspects of the communications manager 4010 described herein.

The request to participate manager 3820 may transmit, to a second AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP.

The intent to participate manager 3825 may receive, from the second APand during the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission.

The trigger signal manager 3830 may transmit, during an initial periodof the second portion of the TxOP, a trigger signal to the second APindicating a set of one or more resources for the second AP during theMU transmission.

The MU transmission manager 3835 may participate, in conjunction withthe second AP and during the second portion of the TxOP, in the MUtransmission.

The request to participate manager 3820 may receive, from a first AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP.

The intent to participate manager 3825 may transmit, to the first AP andduring the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission.

The trigger signal manager 3830 may receive, during an initial period ofthe second portion of the TxOP, a trigger signal from the first APindicating a set of one or more resources for the second AP during theMU transmission.

The MU transmission manager 3835 may participate, in conjunction withthe first AP and during the second portion of the TxOP, in the MUtransmission.

The transmitter 3840 may transmit signals generated by other componentsof the device. In some examples, the transmitter 3840 may be collocatedwith a receiver 3810 in a transceiver module. For example, thetransmitter 3840 may be an example of aspects of the transceiver 4020described with reference to FIG. 40. The transmitter 3840 may utilize asingle antenna or a set of antennas.

FIG. 39 shows a block diagram 3900 of a communications manager 3905 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. The communicationsmanager 3905 may be an example of aspects of a communications manager3715, a communications manager 3815, or a communications manager 4010described herein. The communications manager 3905 may include a requestto participate manager 3910, an intent to participate manager 3915, atrigger signal manager 3920, a MU transmission manager 3925, a channelsounding manager 3930, a control channel assignment manager 3935, and achannel access manager 3940. Each of these modules may communicate,directly or indirectly, with one another (e.g., via one or more buses).

The request to participate manager 3910 may transmit, to a second AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP. In some examples, therequest to participate manager 3910 may receive, from a first AP andduring a first portion of a TxOP, a request to participate in a MUtransmission during a second portion of the TxOP.

In some cases, a duration of the TxOP, an available bandwidth for the MUtransmission, an available spatial dimension for the MU transmissions, aconfiguration for the second AP to transmit the indication of intent, ascheduling for the second AP to transmit the indication of intent, atransmission direction for the MU transmission, an allowableinterference level for the first AP, an identifier of the second AP, anidentifier for a group of APs participating in the MU transmission, atransmit power of the first AP, or a combination thereof. In some cases,a duration of the TxOP, an available bandwidth for the MU transmission,an available spatial dimension for the MU transmissions, a configurationfor the second AP to transmit the indication of intent, a scheduling forthe second AP to transmit the indication of intent, a transmissiondirection for the MU transmission, an allowable interference level forthe first AP, an identifier of the second AP, an identifier for a groupof APs participating in the MU transmission, a transmit power of thefirst AP, or a combination thereof.

The intent to participate manager 3915 may receive, from the second APand during the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission. In some examples,the intent to participate manager 3915 may transmit, to the first AP andduring the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission. In some cases, asimultaneous transmission, a scheduled transmission, or a polledtransmission from the second AP and one or more additional APsparticipating in the MU transmission.

In some cases, the indication of intent further indicates a channelpower measurement request for one or more stations to measure a channelpower using the trigger signal. In some cases, a time resource, afrequency resource, a spatial dimension resource, an orthogonalresource, or a combination thereof. In some cases, a simultaneoustransmission, a scheduled transmission, or a polled transmission fromthe second AP and one or more additional APs participating in the MUtransmission. In some cases, the indication of intent further indicatesa station channel power measurement request for one or more stations tomeasure a channel receive power using the trigger signal. In some cases,a time resource, a frequency resource, a spatial dimension resource, anorthogonal resource, or a combination thereof.

The trigger signal manager 3920 may transmit, during an initial periodof the second portion of the TxOP, a trigger signal to the second APindicating a set of one or more resources for the second AP during theMU transmission. In some examples, the trigger signal manager 3920 mayreceive, during an initial period of the second portion of the TxOP, atrigger signal from the first AP indicating a set of one or moreresources for the second AP during the MU transmission.

In some cases, a guard interval duration for the MU transmission, apreamble configuration for the MU transmission, a transmission directionfor the MU transmission, an allowable interference level for the firstAP, an indication of a channel sounding stage between the trigger signaland a beginning of the MU transmission, or a combination thereof. Insome cases, a guard interval duration for the MU transmission, apreamble configuration for the MU transmission, a transmission directionfor the MU transmission, an allowable interference level for the firstAP, an indication of a channel sounding stage between the trigger signaland a beginning of the MU transmission, or a combination thereof.

The MU transmission manager 3925 may participate, in conjunction withthe second AP and during the second portion of the TxOP, in the MUtransmission. In some examples, the MU transmission manager 3925 mayparticipate, in conjunction with the first AP and during the secondportion of the TxOP, in the MU transmission.

The channel sounding manager 3930 may configure the trigger signal toindicate that channel sounding is to be performed between transmissionof the trigger signal and a beginning of the MU transmission. In someexamples, the channel sounding manager 3930 may perform a channelsounding procedure between the first AP and one or more stationsassociated with the first AP during the channel sounding.

In some examples, the channel sounding manager 3930 may decode thetrigger signal to determine that channel sounding is to be performedbetween reception of the trigger signal and a beginning of the MUtransmission. In some examples, the channel sounding manager 3930 mayperform a channel sounding procedure between the second AP and one ormore stations associated with the second AP during the channel sounding.

The control channel assignment manager 3935 may transmit a controlchannel assignment message to each of one or more stations associatedwith the first AP that are associated with the MU transmission thatassigns a control channel for each station to use to determine aresource allocation for the multi-user transmission.

In some examples, the control channel assignment manager 3935 maytransmit, in a beginning of a data transmission during the MUtransmission, the resource allocation for each station to use for the MUtransmission. In some examples, the control channel assignment manager3935 may transmit, in a single protocol data unit, the intent toparticipate to the first AP and each of one or more stations associatedwith the second AP that are participating in the MU transmission. Insome examples, the control channel assignment manager 3935 may transmit,in a first protocol data unit, the intent to participate to the firstAP. In some examples, the control channel assignment manager 3935 maytransmit, in a second protocol data unit, the intent to participate toeach of one or more stations associated with the second AP that areparticipating in the MU transmission. In some examples, the controlchannel assignment manager 3935 may transmit a control channelassignment message to each of one or more stations associated with thesecond AP that are associated with the MU transmission that assigns acontrol channel for each station to use to determine a resourceallocation for the multi-user transmission. In some examples, thecontrol channel assignment manager 3935 may transmit, in a beginning ofa data transmission during the MU transmission, the resource allocationfor each station to use for the MU transmission.

In some cases, the control channel assignment message is transmitted ina different physical layer protocol data unit than the data transmissionof the MU transmission. In some cases, the control channel assignmentmessage is transmitted in a preamble of a second trigger signal (e.g.,in a per-AP trigger signal) before the data transmission. In some cases,the control channel assignment message is transmitted in a preamble ofthe data transmission. In some cases, the single protocol data unitindicates an identifier for each of the one or more stations. In somecases, the single protocol data unit indicates a channel powermeasurement request for one or more stations to measure a channel powerusing the trigger signal. In some cases, the second protocol data unitindicates an identifier for each of the one or more stations. In somecases, the second protocol data unit indicates a channel powermeasurement request for one or more stations to measure a channel powerusing the trigger signal. In some cases, the control channel assignmentmessage is transmitted in a preamble of the second trigger signal beforethe multi-user transmission. In some cases, the control channelassignment message is transmitted in a preamble of the datatransmission. In some cases, the control channel assignment message istransmitted in a different physical layer protocol data unit than thedata transmission of the MU transmission.

The channel access manager 3940 may obtain access to the channel of theshared radio frequency spectrum band for the TxOP.

FIG. 40 shows a diagram of a system 4000 including a device 4005 thatsupports protocols for multi-AP coordinated MU transmissions inaccordance with aspects of the present disclosure. The device 4005 maybe an example of or include the components of device 905, device 1005,device 1205, device 3705, device 3805, or a AP as described herein. Thedevice 4005 may include components for bi-directional voice and datacommunications including components for transmitting and receivingcommunications, including a communications manager 4010, a networkcommunications manager 4015, a transceiver 4020, an antenna 4025, memory4030, a processor 4040, and an inter-station communications manager4045. These components may be in electronic communication via one ormore buses (e.g., bus 4050).

The communications manager 4010 may be an example of the communicationsmanager 915, or the communications manager 1005, or the communicationsmanager 1210, or the communications manager 3715, or the communicationsmanager 3815, or the communications manager 3905 described herein. Thecommunications manager 4010 may transmit, to a second AP and during afirst portion of a TxOP, a request to participate in a MU transmissionduring a second portion of the TxOP, receive, from the second AP andduring the first portion of the TxOP, an indication of intent toparticipate in the MU transmission during the second portion of theTxOP, the indication of intent including a resource request of thesecond AP for participation in the MU transmission, transmit, during aninitial period of the second portion of the TxOP, a trigger signal tothe second AP indicating a set of one or more resources for the secondAP during the MU transmission, and participate, in conjunction with thesecond AP and during the second portion of the TxOP, in the MUtransmission. The communications manager 4010 may also receive, from afirst AP and during a first portion of a TxOP, a request to participatein a MU transmission during a second portion of the TxOP, transmit, tothe first AP and during the first portion of the TxOP, an indication ofintent to participate in the MU transmission during the second portionof the TxOP, the indication of intent including a resource request ofthe second AP for participation in the MU transmission, receive, duringan initial period of the second portion of the TxOP, a trigger signalfrom the first AP indicating a set of one or more resources for thesecond AP during the MU transmission, and participate, in conjunctionwith the first AP and during the second portion of the TxOP, in the MUtransmission.

The network communications manager 4015 may manage communications withthe core network (e.g., via one or more wired backhaul links). Forexample, the network communications manager 4015 may manage the transferof data communications for client devices, such as one or more STAs 115.

The transceiver 4020 may communicate bi-directionally, via one or moreantennas, wired, or wireless links as described above. For example, thetransceiver 4020 may represent a wireless transceiver and maycommunicate bi-directionally with another wireless transceiver. Thetransceiver 4020 may also include a modem to modulate the packets andprovide the modulated packets to the antennas for transmission, and todemodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 4025.However, in some cases the device may have more than one antenna 4025,which may be capable of concurrently transmitting or receiving multiplewireless transmissions.

The memory 4030 may include RAM and ROM. The memory 4030 may storecomputer-readable, computer-executable code 4035 including instructionsthat, when executed, cause the processor to perform various functionsdescribed herein. In some cases, the memory 4030 may contain, amongother things, a BIOS which may control basic hardware or softwareoperation such as the interaction with peripheral components or devices.

The processor 4040 may include an intelligent hardware device, (e.g., ageneral-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, anFPGA, a programmable logic device, a discrete gate or transistor logiccomponent, a discrete hardware component, or any combination thereof).In some cases, the processor 4040 may be configured to operate a memoryarray using a memory controller. In other cases, a memory controller maybe integrated into processor 4040. The processor 4040 may be configuredto execute computer-readable instructions stored in a memory to performvarious functions (e.g., functions or tasks supporting protocols formulti-AP coordinated MU transmissions).

The inter-station communications manager 4045 may manage communicationswith other APs 105, and may include a controller or scheduler forcontrolling communications with STAs 115 in cooperation with other APs105. For example, the inter-station communications manager 4045 maycoordinate scheduling for transmissions to STAs 115 for variousinterference mitigation techniques such as beamforming or jointtransmission.

FIG. 41 shows a flowchart illustrating a method 4100 that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure. The operations of method 4100 may beimplemented by a AP or its components as described herein. For example,the operations of method 4100 may be performed by a communicationsmanager as described with reference to FIGS. 37 through 40. In someexamples, a AP may execute a set of instructions to control thefunctional elements of the AP to perform the functions described below.Additionally or alternatively, a AP may perform aspects of the functionsdescribed below using special-purpose hardware.

At 4105, the AP may transmit, to a second AP and during a first portionof a TxOP, a request to participate in a MU transmission during a secondportion of the TxOP. The operations of 4105 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 4105 may be performed by a request to participate manageras described with reference to FIGS. 37 through 40.

At 4110, the AP may receive, from the second AP and during the firstportion of the TxOP, an indication of intent to participate in the MUtransmission during the second portion of the TxOP, the indication ofintent including a resource request of the second AP for participationin the MU transmission. The operations of 4110 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 4110 may be performed by an intent to participatemanager as described with reference to FIGS. 37 through 40.

At 4115, the AP may transmit, during an initial period of the secondportion of the TxOP, a trigger signal to the second AP indicating a setof one or more resources for the second AP during the MU transmission.The operations of 4115 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 4115may be performed by a trigger signal manager as described with referenceto FIGS. 37 through 40.

At 4120, the AP may participate, in conjunction with the second AP andduring the second portion of the TxOP, in the MU transmission. Theoperations of 4120 may be performed according to the methods describedherein. In some examples, aspects of the operations of 4120 may beperformed by a MU transmission manager as described with reference toFIGS. 37 through 40.

FIG. 42 shows a flowchart illustrating a method 4200 that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure. The operations of method 4200 may beimplemented by a AP or its components as described herein. For example,the operations of method 4200 may be performed by a communicationsmanager as described with reference to FIGS. 37 through 40. In someexamples, a AP may execute a set of instructions to control thefunctional elements of the AP to perform the functions described below.Additionally or alternatively, a AP may perform aspects of the functionsdescribed below using special-purpose hardware.

At 4205, the AP may transmit, to a second AP and during a first portionof a TxOP, a request to participate in a MU transmission during a secondportion of the TxOP. The operations of 4205 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 4205 may be performed by a request to participate manageras described with reference to FIGS. 37 through 40.

At 4210, the AP may receive, from the second AP and during the firstportion of the TxOP, an indication of intent to participate in the MUtransmission during the second portion of the TxOP, the indication ofintent including a resource request of the second AP for participationin the MU transmission. The operations of 4210 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 4210 may be performed by an intent to participatemanager as described with reference to FIGS. 37 through 40.

At 4215, the AP may configure the trigger signal to indicate thatchannel sounding is to be performed between transmission of the triggersignal and a beginning of the MU transmission. The operations of 4215may be performed according to the methods described herein. In someexamples, aspects of the operations of 4215 may be performed by achannel sounding manager as described with reference to FIGS. 37 through40.

At 4220, the AP may transmit, during an initial period of the secondportion of the TxOP, a trigger signal to the second AP indicating a setof one or more resources for the second AP during the MU transmission.The operations of 4220 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 4220may be performed by a trigger signal manager as described with referenceto FIGS. 37 through 40.

At 4225, the AP may participate, in conjunction with the second AP andduring the second portion of the TxOP, in the MU transmission. Theoperations of 4225 may be performed according to the methods describedherein. In some examples, aspects of the operations of 4225 may beperformed by a MU transmission manager as described with reference toFIGS. 37 through 40.

At 4230, the AP may perform a channel sounding procedure between thefirst AP and one or more stations associated with the first AP duringthe channel sounding. The operations of 4230 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 4230 may be performed by a channel sounding manager asdescribed with reference to FIGS. 37 through 40.

FIG. 43 shows a flowchart illustrating a method 4300 that supportsprotocols for multi-AP coordinated MU transmissions in accordance withaspects of the present disclosure. The operations of method 4300 may beimplemented by a AP or its components as described herein. For example,the operations of method 4300 may be performed by a communicationsmanager as described with reference to FIGS. 37 through 40. In someexamples, a AP may execute a set of instructions to control thefunctional elements of the AP to perform the functions described below.Additionally or alternatively, a AP may perform aspects of the functionsdescribed below using special-purpose hardware.

At 4305, the AP may receive, from a first AP and during a first portionof a TxOP, a request to participate in a MU transmission during a secondportion of the TxOP. The operations of 4305 may be performed accordingto the methods described herein. In some examples, aspects of theoperations of 4305 may be performed by a request to participate manageras described with reference to FIGS. 37 through 40.

At 4310, the AP may transmit, to the first AP and during the firstportion of the TxOP, an indication of intent to participate in the MUtransmission during the second portion of the TxOP, the indication ofintent including a resource request of the second AP for participationin the MU transmission. The operations of 4310 may be performedaccording to the methods described herein. In some examples, aspects ofthe operations of 4310 may be performed by an intent to participatemanager as described with reference to FIGS. 37 through 40.

At 4315, the AP may receive, during an initial period of the secondportion of the TxOP, a trigger signal from the first AP indicating a setof one or more resources for the second AP during the MU transmission.The operations of 4315 may be performed according to the methodsdescribed herein. In some examples, aspects of the operations of 4315may be performed by a trigger signal manager as described with referenceto FIGS. 37 through 40.

At 4320, the AP may participate, in conjunction with the first AP andduring the second portion of the TxOP, in the MU transmission. Theoperations of 4320 may be performed according to the methods describedherein. In some examples, aspects of the operations of 4320 may beperformed by a MU transmission manager as described with reference toFIGS. 37 through 40.

It should be noted that the methods described herein describe possibleimplementations, and that the operations and the steps may be rearrangedor otherwise modified and that other implementations are possible.Furthermore, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wirelesscommunications systems such as code division multiple access (CDMA),time division multiple access (TDMA), frequency division multiple access(FDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and other systems.The terms “system” and “network” are often used interchangeably. A codedivision multiple access (CDMA) system may implement a radio technologysuch as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc.CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releasesmay be commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) iscommonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. Atime division multiple access (TDMA) system may implement a radiotechnology such as Global System for Mobile Communications (GSM). Anorthogonal frequency division multiple access (OFDMA) system mayimplement a radio technology such as Ultra Mobile Broadband (UMB),Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE802.20, Flash-OFDM, etc.

The wireless communications system or systems described herein maysupport synchronous or asynchronous operation. For synchronousoperation, the stations may have similar frame timing, and transmissionsfrom different stations may be approximately aligned in time. Forasynchronous operation, the stations may have different frame timing,and transmissions from different stations may not be aligned in time.The techniques described herein may be used for either synchronous orasynchronous operations.

The downlink transmissions described herein may also be called forwardlink transmissions while the uplink transmissions may also be calledreverse link transmissions. Each communication link describedherein—including, for example, wireless communications system 100 and200 of FIGS. 1 and 2—may include one or more carriers, where eachcarrier may be a signal made up of multiple sub-carriers (e.g., waveformsignals of different frequencies).

The description set forth herein, in connection with the appendeddrawings, describes example configurations and does not represent allthe examples that may be implemented or that are within the scope of theclaims. The term “exemplary” used herein means “serving as an example,instance, or illustration,” and not “preferred” or “advantageous overother examples.” The detailed description includes specific details forthe purpose of providing an understanding of the described techniques.These techniques, however, may be practiced without these specificdetails. In some instances, well-known structures and devices are shownin block diagram form in order to avoid obscuring the concepts of thedescribed examples.

In the appended figures, similar components or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

Information and signals described herein may be represented using any ofa variety of different technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chipsthat may be referenced throughout the description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection withthe disclosure herein may be implemented or performed with ageneral-purpose processor, a DSP, an ASIC, an FPGA or other programmablelogic device, discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. A general-purpose processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, multiple microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration).

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on acomputer-readable medium. Other examples and implementations are withinthe scope of the disclosure and appended claims. For example, due to thenature of software, functions described herein may be implemented usingsoftware executed by a processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items (for example, a list of items prefaced by a phrasesuch as “at least one of” or “one or more of”) indicates an inclusivelist such that, for example, a list of at least one of A, B, or C meansA or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, asused herein, the phrase “based on” shall not be construed as a referenceto a closed set of conditions. For example, an exemplary step that isdescribed as “based on condition A” may be based on both a condition Aand a condition B without departing from the scope of the presentdisclosure. In other words, as used herein, the phrase “based on” shallbe construed in the same manner as the phrase “based at least in parton.”

Computer-readable media includes both non-transitory computer storagemedia and communication media including any medium that facilitatestransfer of a computer program from one place to another. Anon-transitory storage medium may be any available medium that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, non-transitory computer-readable media cancomprise RAM, ROM, electrically erasable programmable read only memory(EEPROM), compact disk (CD) ROM or other optical disk storage, magneticdisk storage or other magnetic storage devices, or any othernon-transitory medium that can be used to carry or store desired programcode means in the form of instructions or data structures and that canbe accessed by a general-purpose or special-purpose computer, or ageneral-purpose or special-purpose processor. Also, any connection isproperly termed a computer-readable medium. For example, if the softwareis transmitted from a website, server, or other remote source using acoaxial cable, fiber optic cable, twisted pair, digital subscriber line(DSL), or wireless technologies such as infrared, radio, and microwave,then the coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave are included in the definition of medium. Disk and disc,as used herein, include CD, laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The description herein is provided to enable a person skilled in the artto make or use the disclosure. Various modifications to the disclosurewill be readily apparent to those skilled in the art, and the genericprinciples defined herein may be applied to other variations withoutdeparting from the scope of the disclosure. Thus, the disclosure is notlimited to the examples and designs described herein, but is to beaccorded the broadest scope consistent with the principles and novelfeatures disclosed herein.

1-29. (canceled)
 30. An apparatus for wireless communication at a firstaccess point (AP), comprising: a first interface; a second interface;and a wireless modem, wherein the wireless modem is configured to:output via the second interface for transmission to a second AP andduring a first portion of a transmission opportunity, a request toparticipate in a multi-user transmission during a second portion of thetransmission opportunity; obtain, via the first interface, an indicationof intent to participate in the multi-user transmission received fromthe second AP during the first portion of the transmission opportunity,wherein the indication of intent is for the second portion of thetransmission opportunity, the indication of intent including a resourcerequest of the second AP for participation in the multi-usertransmission; output, via the second interface for transmission duringan initial period of the second portion of the transmission opportunity,a trigger signal to the second AP indicating a set of one or moreresources for the second AP during the multi-user transmission; andprovide data for transmission, in conjunction with the second AP andduring the second portion of the transmission opportunity, as part ofthe multi-user transmission.
 31. The apparatus of claim 30, wherein thewireless modem is further configured to: configure the trigger signal toindicate that channel sounding is to be performed between transmissionof the trigger signal and a beginning of the multi-user transmission;and perform a channel sounding procedure between the first AP and one ormore stations associated with the first AP during the channel sounding.32. The apparatus of claim 30, wherein the wireless modem is furtherconfigured to: output via the second interface a control channelassignment message for transmission to each of one or more stationsassociated with the first AP that are associated with the multi-usertransmission that assigns a control channel for each station to use todetermine a resource allocation for the multi-user transmission; andoutput via the second interface for transmission, in a beginning of adata transmission during the multi-user transmission, the resourceallocation for each station to use for the multi-user transmission. 33.The apparatus of claim 32, wherein the control channel assignmentmessage is output for transmission in a different physical layerprotocol data unit than the data transmission of the multi-usertransmission.
 34. The apparatus of claim 32, wherein the control channelassignment message is output for transmission in a preamble of a secondtrigger signal before the data transmission.
 35. The apparatus of claim32, wherein the control channel assignment message is output fortransmission in a preamble of the data transmission.
 36. The apparatusof claim 30, wherein the wireless modem is further configured to: obtainaccess to a channel of a shared radio frequency spectrum band for thetransmission opportunity.
 37. The apparatus of claim 30, wherein therequest to participate further indicates at least one of a duration ofthe transmission opportunity, an available bandwidth for the multi-usertransmission, an available spatial dimension for the multi-usertransmission, a configuration for the second AP to transmit theindication of intent, a scheduling for the second AP to transmit theindication of intent, a transmission direction for the multi-usertransmission, an allowable interference level for the first AP, anidentifier of the second AP, an identifier for a group of APsparticipating in the multi-user transmission, a transmit power of thefirst AP, or a combination thereof.
 38. The apparatus of claim 30,wherein the indication of intent is obtained via the first interface inat least one of a simultaneous transmission, a scheduled transmission,or a polled transmission from the second AP and one or more additionalAPs participating in the multi-user transmission.
 39. The apparatus ofclaim 30, wherein the indication of intent further indicates a channelpower measurement request for one or more stations to measure a channelpower using the trigger signal.
 40. The apparatus of claim 30, whereinthe trigger signal further indicates at least one of a guard intervalduration for the multi-user transmission, a preamble configuration forthe multi-user transmission, a transmission direction for the multi-usertransmission, an allowable interference level for the first AP, anindication of a channel sounding stage between the trigger signal and abeginning of the multi-user transmission, or a combination thereof. 41.The apparatus of claim 30, wherein the set of one or more resourcescomprise at least one of a time resource, a frequency resource, aspatial dimension resource, an orthogonal resource, or a combinationthereof.
 42. An apparatus for wireless communication at a second accesspoint (AP), comprising: a first interface; a second interface; and awireless modem, wherein the wireless modem is configured to: obtain, viathe first interface, a request to participate in a multi-usertransmission received from a first AP during a first portion of atransmission opportunity, wherein the request to participate is for asecond portion of the transmission opportunity; output, via the secondinterface, for transmission to the first AP and during the first portionof the transmission opportunity, an indication of intent to participatein the multi-user transmission during the second portion of thetransmission opportunity, the indication of intent including a resourcerequest of the second AP for participation in the multi-usertransmission; obtain, via the first interface, a trigger signal receivedfrom the first AP during an initial period of the second portion of thetransmission opportunity, wherein the trigger signal indicates a set ofone or more resources for the second AP during the multi-usertransmission; and output data via the second interface for transmission,in conjunction with the first AP and during the second portion of thetransmission opportunity, as part of the multi-user transmission. 43.The apparatus of claim 42, wherein the wireless modem is furtherconfigured to: output via the second interface for transmission, in asingle protocol data unit, the indication of intent to participate tothe first AP and each of one or more stations associated with the secondAP that are participating in the multi-user transmission.
 44. Theapparatus of claim 43, wherein the single protocol data unit indicatesan identifier for each of the one or more stations.
 45. The apparatus ofclaim 43, wherein the single protocol data unit indicates a channelpower measurement request for one or more stations to measure a channelpower using the trigger signal.
 46. The apparatus of claim 42, whereinthe wireless modem is further configured to: output, via the secondinterface, for transmission in a first protocol data unit, theindication of intent to participate to the first AP; and output, via thesecond interface, for transmission in a second protocol data unit, theindication of intent to participate to each of one or more stationsassociated with the second AP that are participating in the multi-usertransmission.
 47. The apparatus of claim 46, wherein the second protocoldata unit indicates an identifier for each of the one or more stations.48. The apparatus of claim 46, wherein the second protocol data unitindicates a channel power measurement request for one or more stationsto measure a channel power using the trigger signal.
 49. The apparatusof claim 46, wherein the wireless modem is further configured to:output, via the second interface, a control channel assignment messagefor transmission to each of one or more stations associated with thefirst AP that are associated with the multi-user transmission thatassigns a control channel for each station to use to determine aresource allocation for the multi-user transmission.
 50. The apparatusof claim 46, wherein the set of one or more resources for the second APis transmitted in one or more of: a preamble of a second trigger signalbefore the multi-user transmission or a preamble of the multi-usertransmission.
 51. The apparatus of claim 42, wherein the wireless modemis further configured to: decode the trigger signal to determine thatchannel sounding is to be performed between reception of the triggersignal and a beginning of the multi-user transmission; and perform achannel sounding procedure between the second AP and one or morestations associated with the second AP during the channel sounding. 52.The apparatus of claim 42, wherein the wireless modem is furtherconfigured to: output, via the second interface, a control channelassignment message for transmission to each of one or more stationsassociated with the second AP that are associated with the multi-usertransmission that assigns a control channel for each station to use todetermine a resource allocation for the multi-user transmission; andoutput, via the second interface, for transmission in a beginning of adata transmission during the multi-user transmission, the resourceallocation for each station to use for the multi-user transmission. 53.The apparatus of claim 52, wherein the control channel assignmentmessage is output for transmission in a different physical layerprotocol data unit than the data transmission of the multi-usertransmission.
 54. The apparatus of claim 42, wherein the request toparticipate further indicates at least one of a duration of thetransmission opportunity, an available bandwidth for the multi-usertransmission, an available spatial dimension for the multi-usertransmission, a configuration for the second AP to transmit theindication of intent, a scheduling for the second AP to transmit theindication of intent, a transmission direction for the multi-usertransmission, an allowable interference level for the first AP, anidentifier of the second AP, an identifier for a group of APsparticipating in the multi-user transmission, a transmit power of thefirst AP, or a combination thereof.
 55. The apparatus of claim 42,wherein the indication of intent is provided for transmission in atleast one of a simultaneous transmission, a scheduled transmission, or apolled transmission from the second AP and one or more additional APsparticipating in the multi-user transmission.
 56. The apparatus of claim42, wherein the indication of intent further indicates a station channelpower measurement request for one or more stations to measure a channelreceive power using the trigger signal.
 57. The apparatus of claim 42,wherein the trigger signal further indicates at least one of a guardinterval duration for the multi-user transmission, a preambleconfiguration for the multi-user transmission, a transmission directionfor the multi-user transmission, an allowable interference level for thefirst AP, an indication of a channel sounding stage between the triggersignal and a beginning of the multi-user transmission, or a combinationthereof.
 58. The apparatus of claim 42, wherein the set of one or moreresources comprise at least one of a time resource, a frequencyresource, a spatial dimension resource, an orthogonal resource, or acombination thereof. 59-120. (canceled)
 121. A wireless device,comprising: a wireless modem, wherein the wireless modem is configuredto: receive, from an access point (AP), a control channel assignmentmessage that assigns a control channel for the wireless station to useto determine a resource allocation for a multi-user transmission duringa transmission opportunity; receive, in the assigned control channel andbefore a data transmission of the multi-user transmission, a resourceallocation for the wireless station to use for the multi-usertransmission; and participate, using the resource allocation, in themulti-user transmission with the AP. 122-132. (canceled)